Username Generator using java

CODE :

import java.util.*;

class Username{

 public static void ungenerator(String fname, String lname, String phno)

    {

        String ln= lname.substring(0,2);

        int l = phno.length();

        String phn = "";

        for (int i = 1; i < l; i += 2) {

            phn += String.valueOf((int) Math.pow(Character.getNumericValue(phno.charAt(i)), 2));

        }

        String ph=phn.substring(0,2);

String fn = fname.replaceAll("a", "x");

        String username = fn+ln+"@"+ph;

        System.out.println("Suggested Username : "+username);

    }

    public static void main(String args[]){

    Scanner scanner = new Scanner(System.in);

        System.out.print("Please enter your First Name : ");

        String fname = scanner.next();

System.out.print("Please enter your Last Name : ");

        String lname = scanner.next();

System.out.print("Please enter your Phno : ");

        String phno = scanner.next();

ungenerator(fname,lname,phno);

}}

Inputs and Outputs :