int Walking(int row, int column) {
    if (row < 0 || row == height || column < 0 || column == width)
        return -1;

    if (grid[row][column] != '.')
        return -1;

    if (visitedNeighbors[row][column] == 1)
        return -1;

    visitedNeighbors[row][column] = 1;
    int valueLeft = 1 + Walking(row, column-1);
    int valueRight = 1 + Walking(row, column+1);
    int valueTop = 1 + Walking(row-1, column);
    int valueBottom = 1 + Walking(row+1, column);

    return valueLeft + valueRight + valueTop + valueBottom;
}