k - starting row index m - ending row index l - starting column index n - ending column index i - iterator
k = 0 NEW_LINE l = 0 NEW_LINE m = len ( a ) NEW_LINE n = len ( a [ 0 ] ) NEW_LINE n_k = 0 NEW_LINE n_l = 0 NEW_LINE n_m = m NEW_LINE n_n = n NEW_LINE while ( k < m and l < n ) : NEW_LINE