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 Ruby (2.3.3) (judge verdict: Runtime Error)

n = $stdin.gets.to_i
count = 0
a = 0
b = 0

found_header = false
n.times do
  str = $stdin.gets.strip
  if str[-1]=="A"
    a+=1
    if str[0] !="B"
      found_header = true
    end
  end

  if str[0]=="B"
    b+=1
  end

  count += str.scan("AB").size
end
add =[a, b, n].min
if !found_header
  add -= 1
end
count+= [0, add].max
puts count
end