a matrix is given: 1 2 3 4 5 6 7 8, 8 7 6 5 4 3 2 1, 2 3 4 5 6 7 8 9, 9 8 7 6 5 4 3 2, 1 3 5 7 9 7 5 3, 3 1 5 3 2 6 5 7, 1 7 5 9 7 3 1 5, 2 6 3 5 1 7 3 2.
Define a st
