问ValueError异常在python3？

EN

import random
tries = 15
money = 0
cheat = 0
run = True
random_number = random.randint(1, 20)

while run:
    if cheat >= 1:
        print(random_number)
        cheat -= 1

    guess = input("Pick a number from 1-20! You have " + str(tries) + " tries")
    guess = int(guess)

    if guess == random_number:
        money += 5
        print("You got it right! You got it with " + str(tries) + " tries left", "your balance is", + money)
        again = input("Play again? yes/no")
        if again == "yes":
            random_number = random.randint(1, 20)
        else:
            break

        #store system
        shop = input("Would you like to access the shop? yes/no")
        if shop == "yes":
            try_cost = 10
            cheat_cost = 20

            #if player has enough money
            buy_try = input("Would you like to purchase more tries? price is 10 dollars for 5 tries. yes/no")
            if buy_try == "yes" and money >= 10:
                tries += 5
                money -= 10
                print("You have", tries, "tries", "and", money, "money", "and", cheat, "cheats")

            buy_cheat = input("Would you like to purchase a cheat? price is 20 dollars for 2 cheats")
            if buy_cheat == "yes" and money >= 20:
                cheat += 2
                money -= 20
                print("You have", tries, "tries", "and", money, "money", "and", cheat, "cheats")

            # if player doesn't have enough money
            elif buy_try == "yes" and money != 10:
                print("You don't have enough for that, you have", money, "dollars")
            elif buy_cheat == "yes" and money != 20:
                print("You don't have enough for that, you have", money, "dollars")

    elif guess > random_number:
        print("Try a little lower!")
        tries -= 1
    elif guess < random_number:
        print("Try a little higher!")
        tries -= 1
    if tries == 0:
        print("you ran out of tries!")
        run = False