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 C# (Mono 4.6.2.0) (judge verdict: Accepted)

using System;
using System.Collections.Generic;
using System.Linq;

namespace AtCoder
{
    class Program
    {
        static void Main(string[] args)
        {
            //[summary]A - B +/- A
            var line = ReadLine();
            int a = line[0];
            int b = line[1];

            if (b % a == 0)
            {
                Console.WriteLine(a + b);
            }
            else
            {
                Console.WriteLine(b - a);
            }            
        }

        static List<int> ReadLine()
        {
            var line = Console.ReadLine().TrimEnd();
            var array = line.Split(' ');
            var numbers = new List<int>();

            foreach (var s in array)
            {
                int num = int.Parse(s);
                numbers.Add(num);
            }

            return numbers;
        }
    }
}