Given a matrix of size n*n, and the items in the matrix will be either 0 or 1,

Make a c++ program to count the number of sub-matrices that only contain 0.

Input: The first line of the input contains an integer n, indicating the size of the matrix. Then it follows n 0 or 1 strings in the next n lines, denoting the content of the matrix

Output: an integer in one line, indicating the count of sub-matrices that only contain 0.

Example:

Input:

5 00011 10001 00000 00100 01110

Output:

60

. solve it soon