import sys
import random


class Machine:
    coins = sorted(set([5, 10, 20, 50, 100]))
    price = 5 * random.randint(4, 10)
    state = 0

    def run(self):
        while self.state < self.price:
            print("".center(64, "-"))
            print("# Your balance:", self.state)
            print("# You need:", self.price)
            print("# Accepting coins:", self.coins)

            coin = self.expect_coin()
            self.state += coin
            if self.state >= self.price:
                print("\nOK:", self.state)
                if self.state > self.price:
                    print("You overpaid by:", self.state - self.price)
                return

    def expect_coin(self):
        coin = None
        while coin not in self.coins:
            try:
                coin = int(input("Insert coin> "))
                if coin not in self.coins:
                    print("Unsupported coin:", coin)
            except KeyboardInterrupt as e:
                print("\nGoodbye. No change, sorry.")
                sys.exit(0)
            except:
                continue
        return coin


m = Machine()
m.run()