Codeforces 424A Squats program in java

Squats.java

import java.util.Scanner;
public class Squats
{
    public static void main(String[] args)
    {
        Scanner z=new Scanner(System.in);
        short n=z.nextShort();
        String x=z.next();
        int a=Math.max(x.replaceAll("X", "").length(), x.replaceAll("x", "").length())-n/2;
        System.out.println(a);
        if(x.replaceAll("X", "").length() >= x.replaceAll("x", "").length()){
            for(int i=0;i<a;i++)
                x=x.replaceFirst("x", "X");
            System.out.println(x);
        } else {
            for(int i=0;i<a;i++)
                x=x.replaceFirst("X", "x");
            System.out.println(x);
        }z.close();
    }
}