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 Python (3.4.3) (judge verdict: Runtime Error)

R, G, B, N = map(int, input().split())

def f(a, b):
    sho, amari = int(a/b), a%b
    return sho, amari


def ans(l, m, s):
    cnt = 0

    R_s, R_a = f(N, l)

    for i in range(R_s + 1):
        x = R_a + i * l # R を i 個使う
        G_s, G_a = f(x, m)
        for j in range(G_s + 1):
            y = G_a + j * m # G を j 個使う
            if y % s == 0:
                cnt += 1
    return cnt

li = [R, G, B]
li.sort(reverse=True)

cnt = ans(li[0], li[1], li[2])

print(cnt)