Problem:
Score : 100 points

Problem Statement

Snuke has N integers: 1,2,\ldots,N.
He will choose K of them and give those to Takahashi.

How many ways are there to choose K consecutive integers?

Constraints

All values in input are integers.

1 \leq K \leq N \leq 50

Input

Input is given from Standard Input in the following format:

N K

Output

Print the answer.

Sample Input 1

3 2

Sample Output 1

2

There are two ways to choose two consecutive integers: (1,2) and (2,3).

Sample Input 2

13 3

Sample Output 2

11

Solution in C# (Mono 4.6.2.0) (judge verdict: Runtime Error)

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text.RegularExpressions;
using System.Threading.Tasks;
using static System.Math;

namespace AtCorder
{
    class Program
    {
        public static void Main(string[] args)
        {
            var n = long.Parse(Console.ReadLine());

            long i = n - 1;
            long count = 0;
            while (true)
            {
                var div = n / i;
                var mod = n % i;
                if (div == mod)
                {
                    count += i;

                    i = n / (div + 1) - 1;
                }
                else if (mod > div)
                {
                    i = n / (div + 1) - 1;
                }
                else
                {
                    i--;
                }

                if (i <= 0)
                {
                    break;
                }
            }

            Console.WriteLine(count);
        }
    }
}