The Lone Torchbearer

A group of four people has to cross a bridge. It is dark, and they have to light the path with a flashlight. No more than two people can cross the bridge simultaneously, and the group has only one flashlight. It takes different time for the people in the group to cross the bridge. When two people together goes through the bridge, the time taken by them to cross the bridge is the time taken by the person with highest crossing time.

A crosses the bridge in 1 minute.
B crosses the bridge in 2 minutes.
C crosses the bridge in 5 minutes.
D crosses the bridge in 10 minutes.

What is the minimum time in which they can cross the bridge?