#!/usr/bin/env python3

encryption_buffer = 0x4E6AF4BC

username = input("Enter a username: ")
full_serial = "FIT-"
username_length = len(username)
min_username_length = 5

while(username_length < min_username_length):
    print("[-] Username must be 5 characters long... Try again.")
    username = input("Enter a username: ")
    username_length = len(username)

i = 0
xor_val = ''.join([str(hex(ord(c))[2:]) for c in username[i:i+4]][::-1])
username_length -= 4
encryption_buffer ^= int(xor_val, 16)
while(username_length > 0):
    i += 1
    xor_val = ''.join([str(hex(ord(c))[2:]) for c in username[i:i+4]][::-1])
    encryption_buffer ^= int(xor_val, 16)
    username_length -= 1

full_serial += str(encryption_buffer)

print(f"The serial is: {full_serial}")