class Calculator(object):
def read(self):
"""Read input from stdin"""
return input()
def eval(self, string):
"""Ваш код здесь"""
def loop(self):
line = self.read()
while line != "quit":
value = self.eval(line)
print(value)
# Read next line of input
line = self.read()
if __name__ == '__main__':
calc = Calculator()
calc.loop()