Make the Matrix Beautiful

You are given an $N \times M$ matrix where each element of the matrix consists of an integer color. Let $A[i][j]$ be the color on the matrix in the $i$-th row from the top and $j$-th column from the left. You need to make the matrix *beautiful*. By definition, a matrix is *beautiful* if all the elements of the $i$-th row have color $i$. That is, all the elements of the first row have color $1$,