Problem:
Score : 100 points

Problem Statement

Joisino wants to evaluate the formula "A op B".
Here, A and B are integers, and the binary operator op is either + or -.
Your task is to evaluate the formula instead of her.

Constraints

1≦A,B≦10^9

op is either + or -.

Input

The input is given from Standard Input in the following format:

A op B

Output

Evaluate the formula and print the result.

Sample Input 1

1 + 2

Sample Output 1

3

Since 1 + 2 = 3, the output should be 3.

Sample Input 2

5 - 7

Sample Output 2

-2

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

num = gets.chomp.to_i
a = gets.chomp.split(' ')
if num.odd?
  h = Array.new(num, 0)
  a.each do |i|
    puts '0' if i.to_i.odd?
    h[i.to_i] += 1
  end
  if h[0] != 1 || h.max != 2 || h.include(1)
    puts '0'
  else
    puts 2**(num/2.to_i)
  end
else
  h = Array.new(num, 0)
  a.each do |i|
    puts '0' if i.to_i.even? && i != '0'
    h[i.to_i] += 1
  end
  if h.max > 2 && h.min < 2
    puts '0'
  else
    puts 2**(num/2.to_i)
  end
end