#!/usr/bin/python3
import re
import sys


def main(inp, outp):
    hex = re.compile(r'[0-9a-fA-F]')
    buf = ''
    for line in inp:
        for digit in hex.finditer(line):
            buf += digit.group(0)
            if len(buf) == 2:
                outp.write(bytes([int(buf, 16)]))
                buf = ''

if __name__ == '__main__':
    main(sys.stdin, sys.stdout.buffer)