broken random tests. exemples
([[9, 14, 15, -3, -1, -4, 10, 1, 12], [6, 5, 9, -8, -6, 4, 5, -4, 8]], 0) should equal [9, 14, 15, -3, -1, -4, 10, 1, 12]
([[1, -5, 3, -7, 1, -8, 7, -2], [-5], [3], [-7], [1], [-8], [7], [-2]], 1) should equal [1, -5, 3, -7, 1, -8, 7, -2]
([[11], [2], [5], [4]], 0) should equal [11]