You are given an m x n grid. Each cell of grid represents a street. The street of grid[i][j] can be: You will initially start at the street of the upper-left cell (0, 0). A valid path in the grid is a path that starts from the upper left cell (0, 0) and ends at the bottom-right cell (m - 1, n - 1). The path should only follow the streets. Notice that you are not allowed to change any street. Return true if there is a valid path in the grid or false otherwise.