new_contents: #!/usr/bin/env python3
  
  
  def main():
      shape = input()
      if shape == 'прямоугольник':
          a, b = int(input()), int(input())
          print('{}'.format(a * b))
      if shape == 'треугольник':
          a, b, c = int(input()), int(input()), int(input())
          p = (a + b + c) / 2
          print('{}'.format((p * (p - a) * (p - b) * (p - c)) ** (1/2)))
      if shape == 'круг':
          r = int(input())
          pi = 3.14
          print('{}'.format(pi * r ** 2))
  
  
  if __name__ == '__main__':
      main()
  
subject: Add calc area of shapes