def railfence_encrypt(plaintext, rails):
    plaintext = plaintext.replace(" ", "").lower()
    n = len(plaintext)
    fence = [[] for _ in range(rails)]
    rail = 0
    direction = 1

    for char in plaintext:
        fence[rail].append(char)
        rail += direction

        if rail == 0 or rail == rails - 1:
            direction *= -1

    cipher_text = ''.join(''.join(row) for row in fence)
    return cipher_text

def railfence_decrypt(ciphertext, rails):
    n = len(ciphertext)
    fence = [[None] * n for _ in range(rails)]
    index = 0

    rail = 0
    direction = 1

    for i in range(n):
        fence[rail][i] = '*'
        rail += direction
        if rail == 0 or rail == rails - 1:
            direction *= -1

    for r in range(rails):
        for i in range(n):
            if fence[r][i] == '*':
                fence[r][i] = ciphertext[index]
                index += 1

    plaintext = []
    rail = 0
    direction = 1
    for i in range(n):
        plaintext.append(fence[rail][i])
        rail += direction
        if rail == 0 or rail == rails - 1:
            direction *= -1

    return ''.join(plaintext)

plaintext = "network ecurity"
rails = 3

ciphertext = railfence_encrypt(plaintext, rails)
print(f"Plaintext: {plaintext}")
print(f"Ciphertext: {ciphertext}")

decrypted_text = railfence_decrypt(ciphertext, rails)
print(f"Decrypted text: {decrypted_text}")