Blackjack.java

/*
Chef is playing a variant of Blackjack, where 3 numbers are drawn and each number lies between 1 and 10 (with both 1 and 10 inclusive). Chef wins the game when the sum of these 3 numbers is exactly 21.

Given the first two numbers A and B, that have been drawn by Chef, what should be 3-rd number that should be drawn by the Chef in order to win the game?

Note that it is possible that Chef cannot win the game, no matter what is the 3-rd number. In such cases, report −1 as the answer.

Input Format
The first line will contain an integer T - number of test cases. Then the test cases follow.
The first and only line of each test case contains two integers A and B - the first and second number drawn by the Chef.

Output Format
For each testcase, output the 3-rd number that should be drawn by the Chef in order to win the game. Output −1 if it is not possible for the Chef to win the game.

Constraints
1≤T≤100
1≤A,B≤10

Sample 1:
Input
3
1 10
1 5
4 9

Output
10
-1
8
*/

import java.util.*;

public class Blackjack {
    public static void main(String[] args) throws java.lang.Exception {
        // your code goes here
        Scanner sc = new Scanner(System.in);

        int n = sc.nextInt();

        for (int i = 0; i < n; i++) {
            int x = sc.nextInt();
            int y = sc.nextInt();

            int z = 21 - (x + y);

            System.out.println(z <= 10 ? z : -1);
        }

    }
}