The activities of a PERT network and their corresponding activity time estimates (in weeks) i.e., optimistic (t_o), most likely (t_m), and pessimistic (t_p) are given in the table below.

Activity	Time (in weeks)
	to	tm	tp
1−2	2	4	12
1−3	2	4	6
1−4	3	4	11
2−5	3	6	9
3−4	2	5	14
3−5	3	3	3
4−5	3	6	15
5−6	2	5	8

The expected project length is ________ weeks (in integer).