The mistake on the second floor is not knowing what a relay is.

The problem is that both B and E are experts, but they can only be used once. How to choose!

So we model the following matrix.

5 10 5 3

0 0 0 0

3 9 10 3

4 1 1 4 1

2 1 2 2

The correct result is

Ding came to climb the mountain. Electric bicycle. Run long distances. C come for a swim.

18+34+28+27 = 107 minutes to finish the game.