写出用户输入中的大写字符数

def count_uppercase_characters(input_string):
    count = 0
    for char in input_string:
        if char.isupper():
            count += 1
    return count

# 示例用法
user_input = input("请输入一个字符串：")
uppercase_count = count_uppercase_characters(user_input)
print("大写字符数：", uppercase_count)