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 PHP7 (7.0.15) (judge verdict: Accepted)

<?php
$stdin = trim(fgets(STDIN));
$a = explode(' ', $stdin);
if ($a[0] + $a[1] == 15) {
  echo '+';
} else if ($a[0] * $a[1] == 15) {
  echo '*';
} else {
  echo 'x';
}