Problem:
Score : 100 points

Problem Statement

You are given positive integers A and B.

If A is a divisor of B, print A + B; otherwise, print B - A.

Constraints

All values in input are integers.

1 \leq A \leq B \leq 20

Input

Input is given from Standard Input in the following format:

A B

Output

If A is a divisor of B, print A + B; otherwise, print B - A.

Sample Input 1

4 12

Sample Output 1

16

As 4 is a divisor of 12, 4 + 12 = 16 should be printed.

Sample Input 2

8 20

Sample Output 2

12

Sample Input 3

1 1

Sample Output 3

2

1 is a divisor of 1.

Solution in Ruby (2.3.3) (judge verdict: Runtime Error)

N, M = gets.split.map(&:to_i)
a = N.times.map { gets.split.map(&:to_i) }

foodsLove = Array.new(M)
allLoveCount = 0
M.times{|i| foodsLove[i]=0}

N.times { |people|
  a[people][0].times do |foodsnum|
    foodsLove[a[people][foodsnum]] +=1
  end
}

foodsLove.each do |f|
  if f==N
    allLoveCount+=1
  end
end

print allLoveCount