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.Linq;
using System.IO;
using System.Collections.Generic;
using System.Text;

namespace AtCoder {
    public class Program {
        static int[] getKeys() {
            var Keys = Console.ReadLine().Split(' ');
            int N = Keys.Length;
            int[] Ns = new int[N];
            for (int i = 0; i < N; i++) {
                Ns[i] = int.Parse(Keys[i]);
            }
            return Ns;
        }
        static int[] getKeys(char delimiter) {
            var Keys = Console.ReadLine().Split(delimiter);
            int N = Keys.Length;
            int[] Ns = new int[N];
            for (int i = 0; i < N; i++) {
                Ns[i] = int.Parse(Keys[i]);
            }
            return Ns;
        }

        public static void Show<T>(T[,] map) {
            int H = map.GetLength(0);
            int W = map.GetLength(1);
            Console.WriteLine("-------------------------");
            for (int i = 0; i < H; i++) {
                for (int j = 0; j < W; j++) {
                    Console.Write(map[i, j] + " ");
                }
                Console.WriteLine();
            }
            Console.WriteLine("-------------------------");
        }
        public static void Show<T>(T[,] map, string delimiter) {
            int H = map.GetLength(0);
            int W = map.GetLength(1);
            Console.WriteLine("-------------------------");
            for (int i = 0; i < H; i++) {
                for (int j = 0; j < W; j++) {
                    Console.Write(map[i, j] + delimiter);
                }
                Console.WriteLine();
            }
            Console.WriteLine("-------------------------");
        }
        public static void Show<T>(IEnumerable<T> ts) {
            foreach (var item in ts) {
                Console.Write(item + " ");
            }
            Console.WriteLine();
        }
        public static void Show<T>(IEnumerable<T> ts, string delimiter) {
            foreach (var item in ts) {
                Console.Write(item + delimiter);
            }
            Console.WriteLine();
        }
        static T[] getUniform<T>(int length, T value) {
            T[] Ts = new T[length];
            for (int i = 0; i < length; i++) {
                Ts[i] = value;
            }
            return Ts;
        }
        static void setUniform<T>(T[] ts, T value) {
            int length = ts.Length;
            for (int i = 0; i < length; i++) {
                ts[i] = value;
            }
        }
        static T[,] getUniform<T>(int row, int col, T value) {
            T[,] Ts = new T[row, col];
            for (int i = 0; i < row; i++) {
                for (int j = 0; j < col; j++) {
                    Ts[j, i] = value;
                }
            }
            return Ts;
        }
        static void setUniform<T>(T[,] ts, T value) {
            int N = ts.GetLength(0);
            int M = ts.GetLength(1);
            for (int i = 0; i < M; i++) {
                for (int j = 0; j < N; j++) {
                    ts[j, i] = value;
                }
            }
        }

        static void Main() {
            var Ns = getKeys();
            if (Ns[1] % Ns[0] == 0) {
                Console.WriteLine(Ns[0] + Ns[1]);
            } else {
                Console.WriteLine(Ns[1] - Ns[0]);
            }
        }
    }
}