total = 0
while True:
    user_input = input("請輸入一個正整數（輸入 '0' 結束）：")
    number = int(user_input)
    if number == 0:
        break
    elif number > 0:
        total += number
    else:
        print("請輸入正整數。")
print(f"總和為：{total}")