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
  import math
  
  cadena = list()
  sub = list()
  sub2 = list()
  s = """ Since <fontstyle="vertical−align:inherit;"><fontstyle="vertical−align:inherit;">1+2=3<⁄font><⁄font>, the output should be <fontstyle="vertical−align:inherit;"><fontstyle="vertical−align:inherit;">3<⁄font><⁄font>."""
  salida = """<fontstyle="vertical−align:inherit;"><fontstyle="vertical−align:inherit;">3<⁄font><⁄font>."""
  
  kl = salida.find(">3<")
  
  
  x = s.split()
  j = s.find("1+2=3")
  l = s.find(">3<")
  sub2.append(s[l + 1])
  
  sub.append(s[j : j + 5])
  c = sub[0]
  from itertools import permutations
  
  lines = sys.stdin.readlines()
  for linea in lines:
      c = linea.split()
      c = list(map(str, c))
  
  
  x1 = int(c[0])
  x2 = int(c[2])
  
  operador = c[1]
  
  if operador == "+":
      op = x1 + x2
  if operador == "-":
      op = x1 - x2
  elif operador == "*":
      op = x1 * x2
  if operador == "/":
      op = x1 / x2
  str(op)
  operacion1 = s[j : j + 2]
  my_lst_str = "".join(map(str, c))
  operacion1 = s[j : j + 3]
  men = s.replace(operacion1, my_lst_str)
  s = men
  numero = s[j + 4]
  men1 = salida.replace(salida[74], str(op))
  men = s.replace(numero, str(op))
  print(op)
  
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"}]