编程实现：编写函数实现输入英文星期几的第一个字母，用来判断是星期几，如果第一个字母相同，则继续判断第二个字母，以此类推，要求函数能将判断结果输出。

以下是Python3的代码实现：

def get_weekday(letter):
    if letter == 'M':
        print("Monday")
    elif letter == 'W':
        print("Wednesday")
    elif letter == 'F':
        print("Friday")
    elif letter == 'T':
        next_letter = input("Enter the second letter: ")
        if next_letter == 'u':
            print("Tuesday")
        elif next_letter == 'h':
            print("Thursday")
        else:
            print("Invalid input")
    elif letter == 'S':
        next_letter = input("Enter the second letter: ")
        if next_letter == 'a':
            print("Saturday")
        elif next_letter == 'u':
            print("Sunday")
        else:
            print("Invalid input")
    else:
        print("Invalid input")

letter = input("Enter the first letter: ")
get_weekday(letter.upper())

运行结果如下：

Enter the first letter: t
Enter the second letter: u
Tuesday