You are given an unweighted, undirected tree. Write a program to find a vertex set of minimum size in this tree such that each edge has as least one of its end-points in that set.
The first line contains one integer n (0<n≤105) — number of nodes in the tree. Next n−1 lines contain n−1 edges of that tree. Each line contains a pair (u,v) means there is an edge between node u and node v (1≤u,v≤n).
Print number of nodes in the satisfied vertex set on one line.