TUTORIAL cull branch by evaluate repetitive text fragment

Hey, I am working on a visualisation of my Google Takeout JSON file. My idea is to make a 3D model out of the Raw Data, in which each Point is defined by their (timestampMS, latitudeE7, longitudeE7) (x,y,z). I first used 30 Points to test the equation but the following problem appeared. There are some timestampMS which are without a (latitudeE7 and longitudeE7) and after the evaluation sometimes two branches with timestamps follow each other, I am hoping that someone here has an idea how to filter for this repetative text Patterns and how to errase the first of these timestamp pairs?

I am also wondering if there is a way to compare the timestamp values and only pick the branches, which have a 30 Minute Difference ( 1800 000 MS ). At the Moment I am using the Splitting Mask to reduce the number of values but I can imagine that there is a better way to deal with a big set of data. I am curious to hear about your ideas, thanks a lot in advance.