def fairplay_cipher(text, key):
    cipher = ""
    key_length = len(key)
    for i, char in enumerate(text):
        if char.isalpha():
            ascii_offset = 65 if char.isupper() else 97
            key_char = key[i % key_length]
            key_offset = ord(key_char) - ascii_offset
            cipher += chr((ord(char) + key_offset) % 26 + ascii_offset)
        else:
            cipher += char
    return cipher

# Example usage:
text = input("Enter the plaintext: ")
key = input("Enter the key: ")
result = fairplay_cipher(text, key)
print("Cipher:", result)