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 Java8 (OpenJDK 1.8.0) (judge verdict: Wrong Answer)

import java.io.IOException;
import java.util.HashSet;
import java.util.Scanner;
import java.util.TreeSet;

public class Main {
	
	public static void main(String[] args) throws NumberFormatException, IOException
	{
		new Main().run();
	}
	
	public void run() throws NumberFormatException, IOException
	{
		Scanner file = new Scanner(System.in);
		long N = file.nextLong();
		HashSet<Long> factors = new HashSet<Long>();
		for(long i = 2;i*i<=N;i++)
			if(N%i==0){
				factors.add((long) i);
				factors.add(N/i);
			}
		if(N!=1)
			factors.add(N);
		long sum = 0;
		for(long x:factors)
		{
			long M = x-1;
			if(N/M == N%M)
				sum+=M;
		}
		System.out.println(sum);
	}
	
}