Calvin, Azhaghu, Ishan, Nihar, Brian, Sandeep, Tanishq and Prasun are being chased by the deadly medieval monster, Amphisbaena.

8 logicians,Before them is a bridge, their only hope for survival. The bridge can only hold at most 2 persons at a time. Since it is pitch dark they have to carry a lamp, which has to be walked back and forth the two ends.Each person walks at a different speed. A pair must walk together at the speed of the slower person.

They have to cross the bridge in the minimum possible time, or else they will be engulfed in the pangs of death. What is the minimum time that the logicians would have planned out (in minutes)?

**Details and Assumptions**:

-Crossing time: Calvin-2 minutes, Azhaghu- 3 minutes, Ishan-5 minutes, Nihar-7 minutes, Brian-11 minutes, Sandeep- 13 minutes, Tanishq- 17 minutes, Prasun- 19 minutes.

- Strategies such as throwing the lamp across the bridge etc are not allowed.