View Code of Problem 22

import java.util.Scanner;
import java.util.TreeSet;

public class Main {

	public static void main(String[] args) {
		// TODO Auto-generated method stub
		Scanner sc = new Scanner(System.in);
		String a,b;
		while(sc.hasNext()) {
			a = sc.next();
			b = sc.next();
			char[] ac = a.toCharArray();
			char[] bc = b.toCharArray();
			TreeSet<Character> set = new TreeSet<>();
			for(int i = 0; i < ac.length; i ++) {
				for(int j = 0 ; j < bc.length; j ++) {
					if(ac[i] == bc[j]) {
						set.add(ac[i]);
					}
				}
			}
			for (Character character : set) {
				System.out.print(character);
			}
			System.out.println();
		}
	}

}