Taco's Garden Path

In this problem, you are given a 2D grid representing a garden. Each cell in the grid contains either a 'G' (grass) or an 'R' (rock). Your task is to determine whether there exists a path from the top-left corner (cell (0, 0)) to the bottom-right corner (cell (M-1, N-1)) that goes only through cells containing 'G'. Movement is allowed in the four cardinal directions: up, down, left, and right.

Formally, given a grid of dimensions $M \times N$, you need to check if there is a sequence of cells starting at $(0,0)$ and ending at $(M-1, N-1)$ such that for each consecutive cell $(i,j)$ in the sequence, the absolute difference in their row or column indices is 1, and every cell in the path satisfies grid[i][j] = 'G'.

inputFormat

The input is given via standard input (stdin). The first line contains two integers $M$ and $N$, representing the number of rows and columns in the grid respectively. The following $M$ lines each contain $N$ characters separated by spaces, where each character is either 'G' or 'R'.

outputFormat

Output a single line to standard output (stdout) containing either "Yes" if there exists a valid path from the top-left to the bottom-right cell, or "No" otherwise.## sample

3 3
G G R
G R G
G G G

Yes