import sys
import math
from itertools import cycle

source, target = sys.argv[1:]

target = open(target,"ab")

with open(source, 'rb') as source:
    image_bytes = source.read()
    i = 0
    x = 0
    for n in image_bytes:
        if not (i == 3):
            x = n ^ 0b11111111
            i += 1
        else:
            x = n
            i = 0

        target.write(bytes([x]))

target.close()