View Code of Problem 2591

import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.List;
import java.util.Scanner;
 
public class Main {
	public static void main(String[] args) {
		Scanner scanner = new Scanner(System.in);
		int t = scanner.nextInt();
		scanner.nextLine();
		for(int i=0; i<t; i++) {
			char[] c1 = scanner.nextLine().toCharArray();
			char[] c2 = scanner.nextLine().toCharArray();
			boolean flag = false;
			List<Character> list = new ArrayList();
			for(int j=0; j<c2.length; j++) {
				for(int k=0; k<c1.length; k++) {
					if(c2[j] == c1[k]) {
						list.add(c1[k]);
						c1[k] = '0';
						flag = true;
						break;
					}
				}
			}
			
			if(flag) {
				Collections.sort(list);
				for(char cc: list) {
					System.out.print(cc);
				}
				System.out.println();
			}else {
				System.out.println(-1);
			}
		}
	}
}