Online Judge	Problem Set	Authors	Online Contests	User
Web Board Home Page F.A.Qs Statistical Charts	Problems Submit Problem Online Status Prob.ID:	Register Update your info Authors ranklist	Current Contest Past Contests Scheduled Contests Award Contest	User ID: Password:   Register

Input
6 12
2 5
1 2
1 3
2 4
4 5
2 4
2 3
1 4
1 5
2 3
3 5
5 6
Output
8

Home Page   Go Back  To top

All Rights Reserved 2003-2013 Ying Fuchen,Xu Pengcheng,Xie Di
Any problem, Please Contact Administrator