B'In this problem, a n x m rectangular matrix a is called increasing if, for each row of i , when go from left to right, the values strictly increase (that is, a_{i,1}<a_{i,2}< ... <a_{i,m} ) and for each column j , when go from top to bottom, the values strictly increase (that is, a_{1,j}<a_{2,j}< ... <a_{n,j} ). In a given matrix of non-negative integers, it is necessary to replace each value of 0 with some positive integer so that the resulting matrix is increasing and the sum of its elements is maximum, or find that it is impossible. It is guaranteed that in a given value matrix all values of 0 are contained only in internal cells (that is, not in the first or last row and not in the first or last column). The first line contains integers n and m ( 3 <= n, m <= 500 ) -- the number of rows and columns in the given matrix a . The following lines contain m each of non-negative integers -- the values in the corresponding row of the given matrix: a_{i,1}, a_{i,2}, ... , a_{i,m} ( 0 <= a_{i,j} <= 8000 ). It is guaranteed that for all a_{i,j}=0 , 1 < i < n and 1 < j < m are true. If it is possible to replace all zeros with positive numbers so that the matrix is increasing, print the maximum possible sum of matrix elements. Otherwise, print -1. In the first example, the resulting matrix is as follows: In the second example, the value 3 must be put in the middle cell. In the third example, the desired resultant matrix does not exist. '...