View Code of Problem 101

import  java.util.*;
public class Main {
	public static void main(String[] args) {
		Scanner scanner = new Scanner(System.in);
		while(scanner.hasNext()) {
			String s = scanner.nextLine();
			String ss = s.replace(",", "");
			int count = 0;
			StringBuilder sbBuilder = new StringBuilder();
			for(int i=ss.length()-1; i>=0; i--) {
				sbBuilder.append(ss.charAt(i));
				count++;
				if(count == 3 && i!=0 ) {
					sbBuilder.append(",");
					count = 0;
				}
			}
			System.out.println(sbBuilder.reverse());
		}
	}
}