You are given a series of points on a 71x71 grid. Taking only the first 1024 points, how long is the shortest path from (0, 0) to (70, 70)?

The input is a list of pairs of the form a|b which defines that b must not come before a, an empty line, and then a list of values a,b,c,d.

For each line that is valid for all given a|b rules, sum the middle number of each list.