encryption and decryption

alphabet_lower = [
    'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j',
    'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't',
    'u', 'v', 'w', 'x', 'y', 'z'
]

# Get user input
axd = input("Do you want to decrypt or encrypt:\n ").lower()
text = input("Type your message:\n ").lower()
shift2 = int(input("Enter the shift code:\n "))

# Encryption function
def encrypt(plain_text, shift_amount):
    cipher_text = ""
    for letter in plain_text:
        if letter in alphabet_lower:
            position = alphabet_lower.index(letter)
            new_position = (position + shift_amount) % 26  # Wrap around
            cipher_text += alphabet_lower[new_position]
        else:
            cipher_text += letter  
    print(f"Encoded text is:\n {cipher_text}")

def decrypt(cipher_text, shift_amount):
    plain_text = ""
    for letter in cipher_text:
        if letter in alphabet_lower:
            position = alphabet_lower.index(letter)
            new_position = (position - shift_amount) % 26
            plain_text += alphabet_lower[new_position]
        else:
            plain_text += letter
    print(f"Decoded text is:\n {plain_text}")

# Run based on user choice
if axd == "encrypt":
    encrypt(plain_text=text, shift_amount=shift2)
elif axd == "decrypt":
    decrypt(cipher_text=text, shift_amount=shift2)
else:
    print("Invalid option. Please choose 'encrypt' or 'decrypt'.")