To travel from a place A to place B, there are two different bus routes ` B_(1) , B_(2)` , two different train routes ` T_(1) , T_(2)` and one air route ` A_(1) ` . From place B to place C there is one bus route say ` B_(1) ` two different train routes say ` T_(1) , T_(2)` and one air route ` A_(1)` . Find the number of routes of commuting from place A to place C via place B without using similar mode of transportation.

Answer

13