Taco Grid Navigation

You are given an \(N \times N\) grid consisting of characters '.' representing an empty cell and '#' representing an obstacle. Your task is to determine whether there is a path from the top-left corner (cell \(1,1\)) to the bottom-right corner (cell \(N,N\)) by moving only right or down through empty cells.

If such a path exists, output YES; otherwise, output NO. Note that a valid path cannot pass through cells with obstacles, and the starting and ending cells must be accessible (i.e. they must be '.').

You can approach this problem using depth-first search (DFS) or dynamic programming algorithms. Ensure that your solution reads input from stdin and writes the result to stdout.

inputFormat

The first line contains a single integer \(T\), the number of test cases. Each test case is described as follows:

1. The first line contains an integer \(N\), the size of the grid.
2. The next \(N\) lines each contain a string of length \(N\) consisting only of characters '.' and '#', representing the grid.

Input is read from stdin.

outputFormat

For each test case, output a single line containing YES if there exists a valid path from the top-left to the bottom-right corner (moving only right or down) or NO otherwise. Output is printed to stdout.

## sample

2
3
..#
.#.
...
4
....
..#.
.#..
...#

YES
NO

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