#!/usr/bin/env python

from __future__ import print_function, division
import math

def eval_loop():
    while True:
        result = None
        s = input('Enter your input: ')
        if not s:
            print('No input entered.')
        elif s == 'done':
            return result
        else:
            result = eval(s)
            print(result)

last_value = eval_loop()
print('The last value was:  {}'.format(last_value))

