我是Python的新手，我正在写一段代码来展示一个人在玩幸运七游戏时是如何输钱的。下面是代码：

import random 

# ask for the input
def main():
    money = int(input("Enter the amount of money would like to lose:"))
    global max_money 
    max_money = money
    global count_max 
    count_max = 0
    global count
    count = 0 

# loop 

    die1 = random.randint(1,6)
    die2 = random.randint(1,6)
    count += 1
    while True:
        if die1 + die2 == 7:
            money += 5
        else:
            money -= 1
        if money > max_money:
            max_money = money
            count_max = count

print("You have gone broke after", str(count), "rolls")
print("You should stop after", count_max, "when you had $", max_money)

main()

每当我尝试执行代码时，我都会在终端中收到一条错误消息，指出变量“count”，“count_max”和“max_money”没有定义。我甚至尝试在main函数中将变量设为全局变量，但仍然得到相同的消息。我做错了什么？