assert.equal(gKey([[1, 6, 7, 2, 4],
                    [0, 4, 9, 5, 3],
                    [7, 2, 5, 1, 4],
                    [3, 3, 2, 2, 9],
                    [2, 6, 1, 4, 0]], 9), 45)

Right: 46.