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 Rust (1.15.1) (judge verdict: Accepted)

use std::str::FromStr;
fn main() {
    let mut ab = String::new();
    std::io::stdin().read_line(&mut ab).ok();
    let mut it = ab.split_whitespace().map(|n| usize::from_str(n).unwrap());
    let (a,b) = (it.next().unwrap(),it.next().unwrap());
    if a + b == 15 {
        println!("+");
    } else if a * b == 15 {
        println!("*");
    } else {
        println!("x");
    }
}