Path Finding in a Grid

You are given a grid of size $m \times n$, where each cell is either free (0) or blocked (1). The goal is to determine if there exists a path from the top-left cell $(0,0)$ to the bottom-right cell $(m-1,n-1)$ by moving only right or down. Note that the starting and destination cells must be free. If a valid path exists, print "YES"; otherwise, print "NO".

inputFormat

The input is read from standard input. The first line contains two integers $m$ and $n$, representing the number of rows and columns respectively. Each of the following $m$ lines contains $n$ space-separated integers (0 or 1) indicating the state of each cell in the grid.

outputFormat

Output a single line to standard output containing either "YES" if there exists a path from the top-left to the bottom-right corner, or "NO" otherwise.## sample

3 3
0 1 0
0 0 0
1 1 0

YES