#!/usr/bin/env python

import re
import argparse


def load_file(filename):
    with open(filename) as f:
        for line in f:
            yield line.strip()
    return line

def find_max_char(data):
    letters = set(data)
    letter_max = 0
    letter = None
    for l in letters:
        count = data.count(l)
        if count > letter_max:
            letter_max = count
            letter = l

    return letter

def main(args):
    MESSAGE = ""
    lines = []
    for LINE in load_file(args.input):
        lines.append(LINE)

    for p in range(len(lines[0])):
        token = "".join([x[p] for x in lines])
        MESSAGE = "{}{}".format(MESSAGE, find_max_char(token))

    print(MESSAGE)

if __name__ == "__main__":
    parser = argparse.ArgumentParser(description='AdventOfCode 2016 Day 01')
    parser.add_argument('--input', '-i', action='store',  required=True, help='input file')
    args = parser.parse_args()

    main(args)