In an experiment class, teacher assigns a homework to all the students: take water samples of both rivers.
It’s a huge physical work for Komorebi, so he decides to find the shortest way.
Let’s put the question in a two-dimension plain. Assume the converging point of two rivers is and
two rivers are radiations that start from the converging point. Given the point two rivers go
through respectively.
Komorebi needs to know the shortest distance if he starts from the starting point, passes by two

rivers and finally ends at the ending point.