Minimum Time to Cross Bridge by Four People using Torch

Four people need to cross a bridge at night and they have one torch. The bridge can handle the load of only two people at a time. Person A can take 10 minutes, B takes 7 minutes, C takes 2 minutes and D takes 1 minute to cross the bridge. When two people cross the bridge together, they must move at the slower person’s pace. What’s the minimum time taken by four of them to cross the bridge.