diff --git a/app/build.gradle b/app/build.gradle
index 38b90ba..c5ea66d 100644
--- a/app/build.gradle
+++ b/app/build.gradle
@@ -31,6 +31,7 @@ dependencies {
     testImplementation 'junit:junit:4.12'
     implementation "org.jetbrains.kotlin:kotlin-stdlib-jre7:$kotlin_version"
     implementation 'io.kategory:kategory:0.3.11'
+    implementation "android.arch.lifecycle:extensions:1.0.0"
 
 }
 repositories {
diff --git a/app/src/main/AndroidManifest.xml b/app/src/main/AndroidManifest.xml
index 585c626..263c9e0 100644
--- a/app/src/main/AndroidManifest.xml
+++ b/app/src/main/AndroidManifest.xml
@@ -16,6 +16,7 @@
                 <category android:name="android.intent.category.LAUNCHER" />
             </intent-filter>
         </activity>
+        <activity android:name=".option.OptionActivity" />
     </application>
 
 </manifest>
\ No newline at end of file
diff --git a/app/src/main/java/com/danielecampogiani/androidfunctionalvalidation/Data.kt b/app/src/main/java/com/danielecampogiani/androidfunctionalvalidation/Data.kt
new file mode 100644
index 0000000..de72c10
--- /dev/null
+++ b/app/src/main/java/com/danielecampogiani/androidfunctionalvalidation/Data.kt
@@ -0,0 +1,4 @@
+package com.danielecampogiani.androidfunctionalvalidation
+
+
+data class Data(val mail: String, val phone: String)
diff --git a/app/src/main/java/com/danielecampogiani/androidfunctionalvalidation/MainActivity.kt b/app/src/main/java/com/danielecampogiani/androidfunctionalvalidation/MainActivity.kt
index 0611790..e3abfcd 100644
--- a/app/src/main/java/com/danielecampogiani/androidfunctionalvalidation/MainActivity.kt
+++ b/app/src/main/java/com/danielecampogiani/androidfunctionalvalidation/MainActivity.kt
@@ -1,12 +1,19 @@
 package com.danielecampogiani.androidfunctionalvalidation
 
-import android.support.v7.app.AppCompatActivity
+import android.content.Intent
 import android.os.Bundle
+import android.support.v7.app.AppCompatActivity
+import com.danielecampogiani.androidfunctionalvalidation.option.OptionActivity
+import kotlinx.android.synthetic.main.activity_main.*
 
 class MainActivity : AppCompatActivity() {
 
     override fun onCreate(savedInstanceState: Bundle?) {
         super.onCreate(savedInstanceState)
         setContentView(R.layout.activity_main)
+
+        option_button.setOnClickListener {
+            startActivity(Intent(this, OptionActivity::class.java))
+        }
     }
 }
diff --git a/app/src/main/java/com/danielecampogiani/androidfunctionalvalidation/option/OptionActivity.kt b/app/src/main/java/com/danielecampogiani/androidfunctionalvalidation/option/OptionActivity.kt
new file mode 100644
index 0000000..4e23d25
--- /dev/null
+++ b/app/src/main/java/com/danielecampogiani/androidfunctionalvalidation/option/OptionActivity.kt
@@ -0,0 +1,43 @@
+package com.danielecampogiani.androidfunctionalvalidation.option
+
+import android.arch.lifecycle.Observer
+import android.arch.lifecycle.ViewModelProviders
+import android.os.Bundle
+import android.support.v7.app.AppCompatActivity
+import android.widget.Toast
+import com.danielecampogiani.androidfunctionalvalidation.Data
+import com.danielecampogiani.androidfunctionalvalidation.R
+import kotlinx.android.synthetic.main.activity_input.*
+
+class OptionActivity : AppCompatActivity() {
+
+    override fun onCreate(savedInstanceState: Bundle?) {
+        super.onCreate(savedInstanceState)
+        setContentView(R.layout.activity_input)
+
+        val viewModel = ViewModelProviders.of(this)[OptionViewModel::class.java]
+
+        signup_button.setOnClickListener {
+            viewModel.validate(email.text.toString(), number.text.toString())
+        }
+
+        viewModel.validation.observe(this, Observer {
+            it?.fold(this::handleNone, this::handleSome)
+        })
+
+    }
+
+    private fun handleSome(data: Data) {
+        val message = "Mail: ${data.mail} Phone: ${data.phone}"
+        showMessage(message)
+    }
+
+    private fun handleNone() {
+        val message = getString(R.string.option_wrong)
+        showMessage(message)
+    }
+
+    private fun showMessage(message: String) {
+        Toast.makeText(this, message, Toast.LENGTH_SHORT).show()
+    }
+}
\ No newline at end of file
diff --git a/app/src/main/java/com/danielecampogiani/androidfunctionalvalidation/option/OptionViewModel.kt b/app/src/main/java/com/danielecampogiani/androidfunctionalvalidation/option/OptionViewModel.kt
new file mode 100644
index 0000000..c8a8a90
--- /dev/null
+++ b/app/src/main/java/com/danielecampogiani/androidfunctionalvalidation/option/OptionViewModel.kt
@@ -0,0 +1,23 @@
+package com.danielecampogiani.androidfunctionalvalidation.option
+
+import android.arch.lifecycle.LiveData
+import android.arch.lifecycle.MutableLiveData
+import android.arch.lifecycle.ViewModel
+import com.danielecampogiani.androidfunctionalvalidation.Data
+import kategory.Option
+
+
+class OptionViewModel : ViewModel() {
+
+    private val mutableValidation: MutableLiveData<Option<Data>> = MutableLiveData()
+
+    val validation: LiveData<Option<Data>>
+        get() = mutableValidation
+
+
+    fun validate(mail: String, phoneNumber: String) {
+        val validationResult = validateData(mail, phoneNumber)
+        mutableValidation.value = validationResult
+    }
+
+}
\ No newline at end of file
diff --git a/app/src/main/java/com/danielecampogiani/androidfunctionalvalidation/option/functions.kt b/app/src/main/java/com/danielecampogiani/androidfunctionalvalidation/option/functions.kt
new file mode 100644
index 0000000..2375c0d
--- /dev/null
+++ b/app/src/main/java/com/danielecampogiani/androidfunctionalvalidation/option/functions.kt
@@ -0,0 +1,31 @@
+package com.danielecampogiani.androidfunctionalvalidation.option
+
+import com.danielecampogiani.androidfunctionalvalidation.Data
+import com.danielecampogiani.androidfunctionalvalidation.validMail
+import com.danielecampogiani.androidfunctionalvalidation.validNumber
+import kategory.Option
+import kategory.applicative
+import kategory.ev
+import kategory.some
+
+
+fun validateData(mail: String, phoneNumber: String): Option<Data> {
+
+    return Option.applicative().map2(mail.optionMail(), phoneNumber.optionPhoneNumber()) {
+        Data(it.a, it.b)
+    }.ev()
+
+}
+
+
+private fun String.optionMail(): Option<String> =
+        when {
+            validMail(this) -> this.some()
+            else -> Option.None
+        }
+
+private fun String.optionPhoneNumber(): Option<String> =
+        when {
+            validNumber(this) -> this.some()
+            else -> Option.None
+        }
\ No newline at end of file
diff --git a/app/src/main/res/layout/activity_input.xml b/app/src/main/res/layout/activity_input.xml
index d4897a6..bc0ec51 100644
--- a/app/src/main/res/layout/activity_input.xml
+++ b/app/src/main/res/layout/activity_input.xml
@@ -50,7 +50,7 @@
     </android.support.design.widget.TextInputLayout>
 
     <android.support.v7.widget.AppCompatButton
-        android:id="@+id/button"
+        android:id="@+id/signup_button"
         android:layout_width="wrap_content"
         android:layout_height="wrap_content"
         android:backgroundTint="@color/primary"
diff --git a/app/src/main/res/layout/activity_main.xml b/app/src/main/res/layout/activity_main.xml
index 27555a3..2917e10 100644
--- a/app/src/main/res/layout/activity_main.xml
+++ b/app/src/main/res/layout/activity_main.xml
@@ -6,10 +6,13 @@
     android:layout_height="match_parent"
     tools:context="com.danielecampogiani.androidfunctionalvalidation.MainActivity">
 
-    <TextView
+    <android.support.v7.widget.AppCompatButton
+        android:id="@+id/option_button"
         android:layout_width="wrap_content"
         android:layout_height="wrap_content"
-        android:text="Hello World!"
+        android:backgroundTint="@color/primary"
+        android:text="@string/option"
+        android:textColor="@color/icons"
         app:layout_constraintBottom_toBottomOf="parent"
         app:layout_constraintLeft_toLeftOf="parent"
         app:layout_constraintRight_toRightOf="parent"
diff --git a/app/src/main/res/values/strings.xml b/app/src/main/res/values/strings.xml
index ebbff60..35ef0bb 100644
--- a/app/src/main/res/values/strings.xml
+++ b/app/src/main/res/values/strings.xml
@@ -3,4 +3,6 @@
     <string name="mail">Mail</string>
     <string name="phone_number">Phone Number</string>
     <string name="sign_up">Sign Up</string>
+    <string name="option" translatable="false">Option</string>
+    <string name="option_wrong">At least one field is wrong</string>
 </resources>