output_description: Evaluate the formula and print the result.
  
  * * *
input_description: The input is given from Standard Input in the following format:
  
      
      
      A op B
attempt: import sys
  from io import StringIO
  import unittest
  
  
  def resolve():
      input_string = list(input())
      num1 = int(input_string[0])
      num2 = int(input_string[4])
      operater = input_string[2]
  
      result = 0
      if operater == "+":
          result = num1 + num2
      elif operater == "-":
          result = num1 - num2
  
      print(result)
  
  
  class TestClass(unittest.TestCase):
      def assertIO(self, input, output):
          stdout, stdin = sys.stdout, sys.stdin
          sys.stdout, sys.stdin = StringIO(), StringIO(input)
          resolve()
          sys.stdout.seek(0)
          out = sys.stdout.read()[:-1]
          sys.stdout, sys.stdin = stdout, stdin
          self.assertEqual(out, output)
  
      def test_入力例_1(self):
          input = """1 + 2"""
          output = """3"""
          self.assertIO(input, output)
  
      def test_入力例_2(self):
          input = """5 - 7"""
          output = """-2"""
          self.assertIO(input, output)
  
  
  if __name__ == "__main__":
      unittest.main()
  
problem_description: 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.
samples: [{"input": "1 + 2", "output": "3\n    \n\nSince 1 + 2 = 3, the output should be 3.\n\n* * *"}, {"input": "5 - 7", "output": "-2"}]