Problem:
Score : 100 points

Problem Statement

You are given two integers a and b.
Determine if a+b=15 or a\times b=15 or neither holds.

Note that a+b=15 and a\times b=15 do not hold at the same time.

Constraints

1 \leq a,b \leq 15

All values in input are integers.

Input

Input is given from Standard Input in the following format:

a b

Output

If a+b=15, print +;
if a\times b=15, print *;
if neither holds, print x.

Sample Input 1

4 11

Sample Output 1

+

4+11=15.

Sample Input 2

3 5

Sample Output 2

*

3\times 5=15.

Sample Input 3

1 1

Sample Output 3

x

1+1=2 and 1\times 1=1, neither of which is 15.

Solution in Java8 (OpenJDK 1.8.0) (judge verdict: Accepted)

import java.math.BigInteger;
import java.util.*;


public class Main {
	
	
	private void doit(){
		Scanner sc = new Scanner(System.in);
		while(sc.hasNext()){
			int a = sc.nextInt();
			int b = sc.nextInt();
			if(a + b == 15){
				System.out.println("+");
			}
			else if(a * b == 15){
				System.out.println("*");
			}
			else{
				System.out.println("x");
			}
		}
	}

	private void debug(Object... o) {
		System.out.println("debug = " + Arrays.deepToString(o));
	}

	public static void main(String[] args) {
		new Main().doit();
	}

}