Roman Numeral

import java.util.*;
public class RomanNumeral
{
    public static void main(String[] args){
        System.out.println("This program will take a number and output it as a Roman Numeral. ");
        System.out.println("\nPlease enter a number between 1 and 3999: ");
        Scanner input = new Scanner(System.in);
        long number = input.nextLong();
        int i = 0;
        String romanNum = "";
        if (number < 1 || number > 3999){
            System.out.println("\nInvalid Input");
        }
        else{
            while(i < number){
                romanNum = romanNum + "I";
                i++;
            }
            romanNum = romanNum.replaceAll("IIIII","V").replaceAll("IIII","IV").replaceAll("VV","X").replaceAll("VIV","IX").replaceAll("XXXXX","L").replaceAll("XXXX","XL").replaceAll("LL","C").replaceAll("LXL","XC").replaceAll("CCCCC","D").replaceAll("CCCC","CD").replaceAll("DD","M").replaceAll("DCD","CM");
            System.out.println(number+" in Roman Numerals is " + romanNum);
        }
    }
}