diff --git a/.idea/workspace.xml b/.idea/workspace.xml
index 07aa07a..a6a5562 100644
--- a/.idea/workspace.xml
+++ b/.idea/workspace.xml
@@ -3,7 +3,6 @@
   <component name="ChangeListManager">
     <list default="true" id="7b82e9dd-1613-4d61-85d3-defaa6d2a9fc" name="Default Changelist" comment="">
       <change beforePath="$PROJECT_DIR$/.idea/workspace.xml" beforeDir="false" afterPath="$PROJECT_DIR$/.idea/workspace.xml" afterDir="false" />
-      <change beforePath="$PROJECT_DIR$/README.md" beforeDir="false" afterPath="$PROJECT_DIR$/README.md" afterDir="false" />
     </list>
     <option name="SHOW_DIALOG" value="false" />
     <option name="HIGHLIGHT_CONFLICTS" value="true" />
@@ -178,7 +177,7 @@
       <workItem from="1623421561322" duration="781000" />
       <workItem from="1623434552417" duration="4413000" />
       <workItem from="1623439122821" duration="65000" />
-      <workItem from="1623480171530" duration="69000" />
+      <workItem from="1623480171530" duration="505000" />
     </task>
     <task id="LOCAL-00001" summary="imnit">
       <created>1623307775155</created>
@@ -432,7 +431,14 @@
       <option name="project" value="LOCAL" />
       <updated>1623439179293</updated>
     </task>
-    <option name="localTasksCounter" value="37" />
+    <task id="LOCAL-00037" summary="factorial">
+      <created>1623480481843</created>
+      <option name="number" value="00037" />
+      <option name="presentableId" value="LOCAL-00037" />
+      <option name="project" value="LOCAL" />
+      <updated>1623480481843</updated>
+    </task>
+    <option name="localTasksCounter" value="38" />
     <servers />
   </component>
   <component name="TypeScriptGeneratedFilesManager">
@@ -462,10 +468,10 @@
       <screen x="1920" y="0" width="1920" height="1080" />
     </state>
     <state x="2338" y="180" key="#com.intellij.execution.impl.EditConfigurationsDialog/0.27.1920.1017/1920.0.1920.1080@1920.0.1920.1080" timestamp="1623348070162" />
-    <state x="467" y="128" width="967" height="822" key="CommitChangelistDialog2" timestamp="1623439179188">
+    <state x="467" y="128" width="967" height="822" key="CommitChangelistDialog2" timestamp="1623480481744">
       <screen x="0" y="27" width="1920" height="1017" />
     </state>
-    <state x="467" y="128" width="975" height="822" key="CommitChangelistDialog2/0.27.1920.1017/1920.0.1920.1080@0.27.1920.1017" timestamp="1623439179188" />
+    <state x="467" y="128" width="975" height="822" key="CommitChangelistDialog2/0.27.1920.1017/1920.0.1920.1080@0.27.1920.1017" timestamp="1623480481744" />
     <state x="2387" y="107" width="967" height="822" key="CommitChangelistDialog2/0.27.1920.1017/1920.0.1920.1080@1920.0.1920.1080" timestamp="1623435751554" />
     <state width="1874" height="325" key="GridCell.Tab.0.bottom" timestamp="1623438965809">
       <screen x="0" y="27" width="1920" height="1017" />
@@ -507,15 +513,15 @@
     </state>
     <state width="1874" height="325" key="GridCell.Tab.1.right/0.27.1920.1017/1920.0.1920.1080@0.27.1920.1017" timestamp="1623438965808" />
     <state width="1874" height="336" key="GridCell.Tab.1.right/0.27.1920.1017/1920.0.1920.1080@1920.0.1920.1080" timestamp="1623401535127" />
-    <state x="555" y="271" width="800" height="535" key="Vcs.Push.Dialog.v2" timestamp="1623439180681">
+    <state x="555" y="271" width="800" height="535" key="Vcs.Push.Dialog.v2" timestamp="1623480484009">
       <screen x="0" y="27" width="1920" height="1017" />
     </state>
-    <state x="555" y="271" width="800" height="535" key="Vcs.Push.Dialog.v2/0.27.1920.1017/1920.0.1920.1080@0.27.1920.1017" timestamp="1623439180681" />
+    <state x="555" y="271" width="800" height="535" key="Vcs.Push.Dialog.v2/0.27.1920.1017/1920.0.1920.1080@0.27.1920.1017" timestamp="1623480484009" />
     <state x="2475" y="259" width="800" height="535" key="Vcs.Push.Dialog.v2/0.27.1920.1017/1920.0.1920.1080@1920.0.1920.1080" timestamp="1623435753293" />
-    <state x="616" y="363" key="com.intellij.ide.util.TipDialog" timestamp="1623480171858">
+    <state x="616" y="363" key="com.intellij.ide.util.TipDialog" timestamp="1623480908332">
       <screen x="0" y="27" width="1920" height="1017" />
     </state>
-    <state x="616" y="363" key="com.intellij.ide.util.TipDialog/0.27.1920.1017/1920.0.1920.1080@0.27.1920.1017" timestamp="1623480171858" />
+    <state x="616" y="363" key="com.intellij.ide.util.TipDialog/0.27.1920.1017/1920.0.1920.1080@0.27.1920.1017" timestamp="1623480908332" />
     <state x="2536" y="357" key="com.intellij.ide.util.TipDialog/0.27.1920.1017/1920.0.1920.1080@1920.0.1920.1080" timestamp="1623393428074" />
     <state x="2648" y="442" width="464" height="167" key="com.intellij.openapi.vcs.update.UpdateOrStatusOptionsDialogupdate-v2" timestamp="1623405372701">
       <screen x="1920" y="0" width="1920" height="1080" />
diff --git a/go.mod b/go.mod
index 32b6945..44f36ec 100644
--- a/go.mod
+++ b/go.mod
@@ -1,3 +1,3 @@
-module github.com/digital-technology-agency/math
+module github.com/digital-technology-agency/math@v1
 
 go 1.15