http://www.cnblogs.com/skyhacker/archive/2012/02/03/2337572.html
http://blog.youkuaiyun.com/demon24/article/details/8502565
I=lambda:map(int,raw_input().split())
n,k=I()
a=I()
http://www.cnblogs.com/skyhacker/archive/2012/02/03/2337572.html
http://blog.youkuaiyun.com/demon24/article/details/8502565
I=lambda:map(int,raw_input().split())
n,k=I()
a=I()