Given a list of integers nums, find the length of the longest subsequence (not necessarily contiguous) that satisfies both of the following: 1) consecutive elements in the subsequence alternate sign (positive vs negative); 2) the absolute values are non-decreasing along the subsequence (each next absolute value is >= the previous). Zeros are ignored (cannot be part of the subsequence). Return the length of such longest subsequence.
([1, -2, 3, -4, 5])5