Problem:
Score : 100 points

Problem Statement

You are given positive integers A and B.

If A is a divisor of B, print A + B; otherwise, print B - A.

Constraints

All values in input are integers.

1 \leq A \leq B \leq 20

Input

Input is given from Standard Input in the following format:

A B

Output

If A is a divisor of B, print A + B; otherwise, print B - A.

Sample Input 1

4 12

Sample Output 1

16

As 4 is a divisor of 12, 4 + 12 = 16 should be printed.

Sample Input 2

8 20

Sample Output 2

12

Sample Input 3

1 1

Sample Output 3

2

1 is a divisor of 1.

Solution in Rust (1.15.1) (judge verdict: Accepted)

use std::io::stdin;

macro_rules! read {
    ($t: ty) => {{
        let mut line = String::new();
        stdin().read_line(&mut line);
        line.trim().parse::<$t>().unwrap()
    }};
    ($($t: ty), *) => {{
        let mut line = String::new();
        stdin().read_line(&mut line);
        let mut iter = line.split_whitespace();
        (
            $(iter.next().unwrap().parse::<$t>().unwrap(), )*
        )
    }}
}
macro_rules! reads {
    ($e:expr, $t:ty) => {{
        let mut v = vec![];
        for _ in 0..$e {
            let mut line = String::new();
            stdin().read_line(&mut line);
            v.push(line.trim().parse::<$t>().unwrap());
        }
        v
    }};
}

fn main() {
    let (a, b) = read!(u32, u32);
    if b % a == 0 {
        println!("{}", b + a);
    } else {
        println!("{}", b - a);
    }
}