#!/usr/bin/env python

import re
import argparse

KEYPAD = {
    '1': {'U': None, 'D': '3', 'L': None, 'R': None },
    '2': {'U': None, 'D': '6', 'L': None, 'R': '3' },
    '3': {'U': '1', 'D': '7', 'L': '2', 'R': '4' },
    '4': {'U': None, 'D': '8', 'L': '3', 'R': None },
    '5': {'U': None, 'D': None, 'L': None, 'R': '6' },
    '6': {'U': '2', 'D': 'A', 'L': '5', 'R': '7' },
    '7': {'U': '3', 'D': 'B', 'L': '6', 'R': '8' },
    '8': {'U': '4', 'D': 'C', 'L': '7', 'R': '9' },
    '9': {'U': None, 'D': None, 'L': '8', 'R': None },
    'A': {'U': '6', 'D': None, 'L': None, 'R': 'B' },
    'B': {'U': '7', 'D': 'D', 'L': 'A', 'R': 'C' },
    'C': {'U': '8', 'D': None, 'L': 'B', 'R': None },
    'D': {'U': 'B', 'D': None, 'L': None, 'R': None }
}

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 KEY_NEW is None:
                continue
            KEY = KEY_NEW
        CODE = "{}{}".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)