You are given a String blocks representing the layout of a city. Each character of each element of blocks represents one city block. A 'B' character represents a bus stop, and a '-' represents all other spaces.
The fare for traveling on the bus is equal to the manhattan distance (difference in X-coordinates plus difference in Y-coordinates, see the first example for clarification) between the starting and ending bus stops. Return the largest possible fare for a trip from one bus stop to another.