usernamegeneration solution

import java.io.*;
import java.util.*;
import java.text.*;
import java.math.*;
import java.util.regex.*;

public class Solution {

   private static String output1;

   public static void userIdGeneration(String input1, String input2, int input3, int input4) {
     //Write your code here
    String longer="";
    String smaller="";
    int l1=input1.length();
    int l2=input2.length();
    output1="";

    if(l1==l2)
    {
    if(input1.compareTo(input2)>0)
    {
    longer=input1;
    smaller=input2;
       }
    else
    {
    longer=input2;
    smaller=input1;
    }
    }else if(l1>l2){
    longer=input1;
     smaller=input2;
    }
else
{
longer=input2;
smaller=input1;
}
String number=input3+"";
String output=longer.charAt(0)+smaller+number.charAt(input4-1)+number.charAt(number.length()-input4);
for(int i=0;i<output.length();i++)
{
if(Character.isUpperCase(output.charAt(i)))
{
output1+=Character.toLowerCase(output.charAt(i));
}
else if(Character.isLowerCase(output.charAt(i)))
{
output1+=Character.toUpperCase(output.charAt(i));
}
else
{
output1+=output.charAt(i);
}
}
}

   public static void main(String[] args) {
        /* Do NOT Alter main() */
     Scanner in=new Scanner(System.in);
     String input1=in.next();
     String input2=in.next();
     int input3=in.nextInt();
     int input4=in.nextInt();
     userIdGeneration(input1, input2, input3, input4);
     System.out.println(output1);
    }
}