def login():
    while True:
        username = input("Please enter your username ")
        password = input("Please enter your password ")
        with sqlite3.connect("Timetable.db") as db:
            cursor = db.cursor()
        find_user = ("SELECT * FROM students WHERE username = ? AND password = ?")
        cursor.execute(find_user,[(username),(password)])
        results = cursor.fetchall()
        if results:
            print("Welcome")
            break
        else:
            print("Username and password wrong ")
            again = input("try again? (y/n):  ")
            if again.lower() == "n":
                print("bye")
                time.sleep(1)
                break