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 JavaScript (node.js v5.12) (judge verdict: Runtime Error)

function main() {
    var strNum = input[0] +1;
    var result = 0;
    for (var i = 1; i < strNum; i++){
        result += Number(input[i].split("AB").length) - 1;
    };
  
  	for(var j = 1;j < strNum; j++){
      for(var n = 1;n < strNum; n++){
        if(n == j){
          continue;
        }        
      	if((input[j].toString().slice(-1) + input[n].toString().slice(0,1)) === 'AB'){
        	result++;
        };
      }
    }
    console.log(result);
};

main(require('fs').readFileSync('/dev/stdin', 'utf8'));