void timer(int** Map)
{
    vector<pair<int, int> > wave;
    vector<pair<int, int> > oldWave;
    oldWave.push_back(pair<int, int>(1, 1));
    int nstep = 0;
    map[1][1] = nstep;
    const int dx[] = { 0, 1, 0, -1 };
    const int dy[] = { -1, 0, 1, 0 };
    while (oldWave.size() > 0)
    {
        ++nstep;
        wave.clear();
        for (vector<pair<int, int> >::iterator i = oldWave.begin(); i != oldWave.end(); ++i)
        {
            for (int d = 0; d < 4; ++d)
            {
                int nx = i->first + dx[d];
                int ny = i->second + dy[d];
                if (map[nx][ny] == -1)
                {
                    wave.push_back(pair<int, int>(nx, ny));
                    map[nx][ny] = nstep;
                    if (nx == N - 2 && ny == N - 2)
                        goto done;
                    for (int b = 0; b < 10000; ++b)
                    {
                    }
                }
            }
        }
        oldWave = wave;
    }
done:
    int x = N - 2;
    int y = N - 2;
    wave.clear();
    wave.push_back(pair<int, int>(x, y));
    while (map[x][y] != 0)
    {
        for (int d = 0; d < 4; ++d)
        {
            int nx = x + dx[d];
            int ny = y + dy[d];
            if (map[x][y] - 1 == map[nx][ny])
            {
                x = nx;
                y = ny;
                wave.push_back(pair<int, int>(x, y));
                break;
            }
        }
    }
}