During the Mult-University Trainging,Coach Yehr asks all the ACM teammates to jog at 6:30AM.But 6:30 is too early,there are always somebody might be late.Coach Yehr likes AC sequence very much,the AC sequence is a number sequence with all the elements different.A sequence (S1 ,S2 ,S3 ……Sn ) is a AC sequence if S1 ,S2 ,S3 ……Sn are all different. There are N teammates,the time(in second time) every teammate’arrival make a number sequence with length N. In order to punish the laters,Coach Yehr give them a puzzle,Coach Yehr choose a subsequence from Sa to Sb ,the laters must tell Coach Yehr the longest length of AC sequence in the subsequence as soon as possible.