B'You are given a grid with n rows and m columns. We denote the square on the i -th ( 1 <= i <= n ) row and j -th ( 1 <= j <= m ) column by (i, j) and the number there by a_{ij} . All numbers are equal to 1 or to -1 . You start from the square (1, 1) and can move one square down or one square to the right at a time. In the end, you want to end up at the square (n, m) . Is it possible to move in such a way so that the sum of the values written in all the visited cells (including a_{11} and a_{nm} ) is 0 ? Each test contains multiple test cases. The first line contains the number of test cases t ( 1 <= q t <= q 10^4 ). Description of the test cases follows. The first line of each test case contains two integers n and m ( 1 <= n, m <= 1000 ) -- the size of the grid. Each of the following n lines contains m integers. The j -th integer on the i -th line is a_{ij} ( a_{ij} = 1 or -1 ) -- the element in the cell (i, j) . It is guaranteed that the sum of n cdot m over all test cases does not exceed 10^6 . For each test case, print "YES" if there exists a path from the top left to the bottom right that adds up to 0 , and "NO" otherwise. You can output each letter in any case. One possible path for the fourth test case is given in the picture in the statement. '...