print("Plaintext:", end = "")
    plain = get_string("")  # Get message
    n = len(plain)
    for i in plain:
        if i.isupper:
            print(chr((((ord(i) - ord('A'))+ k) % 26) + ord('A')), end = "")
        elif i.islower:
            print(chr((((ord(i) - ord('a'))+ k) % 26) + ord('a')), end = "")
            print(i)
        else:
            print(i, end = "")
    print("")