#!/usr/bin/env python3

import sys
from copy import deepcopy


if __name__ == '__main__':
    oasis = [[int(n) for n in line.strip('\n').split(' ')] for line in open(sys.argv[1])]

    res1, res2 = 0, 0
    for row in oasis:
        array = []
        array.append(deepcopy(row))
        for i in range(len(row)):
            array.append([])
            for k,v in enumerate(array[i][1:]):
                array[i+1].append(v - array[i][k])
            # challenge 1
            res1 += array[i][-1]
            if sum(array[i+1]) == 0: break
        # challenge 2
        p = 0
        for a in reversed(array):
            p = a[0] - p
        res2 += p

    res1 = str(res1)
    print(f"challenge 1:\n{res1}\n")

    res2 = str(res2)
    print(f"challenge 2:\n{res2}\n")