#!/usr/bin/env python3

import sys
from copy import deepcopy

def cprint(cucs):
    for l in cucs:
        print(''.join(l))
    print('\n')

def step(cucs):
    nc = deepcopy(cucs)
    for y,l in enumerate(cucs):
        for x,c in enumerate(l):
            if c == '>':
                if cucs[y][(x+1)%len(l)] == '.':
                    nc[y][x] = '.'
                    nc[y][(x+1)%len(l)] = '>'
    cucs = deepcopy(nc)
    for y,l in enumerate(cucs):
        for x,c in enumerate(l):
            if c == 'v':
                if cucs[(y+1)%len(cucs)][x] == '.':
                    nc[y][x] = '.'
                    nc[(y+1)%len(cucs)][x] = 'v'
    return nc

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

    # challenge 1
    nc = []
    i = 0
    while nc != cucs:
        print(i)
        i += 1
        cprint(nc)
        cucs = deepcopy(nc) if nc != [] else cucs
        nc = step(cucs)

    res1 = str(i)
    print("challenge 1:" + "\n" +  res1 + "\n")

    # challenge 2
    res2 = "doesn't exist :)"
    print("challenge 2:" + "\n" +  res2 + "\n")