# From chapter 4 of "Stealing the Network", "h3x's Adventures in Networkland",
# the last line of text.
#
# H3x herself could of course just read it.
# But mere mortals like us need to decode it, eh?
#
# Now, in any other context, I would document, test, and sign this.
# But here? Let 'er rip.

h3x = "49207374696c6c206f776e20796f757220617373"

def pairs(hexstr):
    if not hexstr: return []
    return [ hexstr[0:2] ] + pairs(hexstr[2:])  # Recursion, anyone?

def letter(pair):              # Base 16 is just like base 10
    return chr(int(pair, 16))  # ... if you have six extra fingers.

def joinem(letters):
    return ''.join(letters)  # Python's string API. Sigh.

print(joinem([letter(p) for p in pairs(h3x)]))