#!/usr/bin/env python

import re
import argparse

KEYPAD = {
    1: {'U': 0, 'D': 4, 'L': 0, 'R': 2 },
    2: {'U': 0, 'D': 5, 'L': 1, 'R': 3 },
    3: {'U': 0, 'D': 6, 'L': 2, 'R': 0 },
    4: {'U': 1, 'D': 7, 'L': 0, 'R': 5 },
    5: {'U': 2, 'D': 8, 'L': 4, 'R': 6 },
    6: {'U': 3, 'D': 9, 'L': 5, 'R': 0 },
    7: {'U': 4, 'D': 0, 'L': 0, 'R': 8 },
    8: {'U': 5, 'D': 0, 'L': 7, 'R': 9 },
    9: {'U': 6, 'D': 0, 'L': 8, 'R': 0 }
}

def load_file(filename):
    with open(filename) as f:
        data = f.readlines()
    return data

def main(args):
    KEY = 5
    CODE = ""
    for LINE in load_file(args.input):
        LINE = LINE.strip()
        for STEP in LINE:
            KEY_NEW = KEYPAD[KEY][STEP]
            if not KEY_NEW:
                continue
            KEY = KEY_NEW
        CODE = "{}{:d}".format(CODE, KEY)

    print(CODE)

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)