Jack and Rose are playing games after working out so many difficult problems. They together drew a “Haizi” tree to show their collaboration. “Haizi” tree is the same as the tree defined in graph theory.

Now Jack would like to count the number of vertices whose degree is one in this tree. You need to help him with this calculation.

: The degree of a vertex of a graph is the number of edges that are connected with the vertex.

The first line contains an integer  () --- the number of vertices.
The next  lines describe the edges of the tree, where the -th line contains two integers ,  () --- the two vertices that is connected by the -th edge.

Output one integers in one line --- the number of vertices whose degree is one.

5
1 2
2 3
1 4
4 5

2

As shown in figure below, only the vertex  and vertex  are connected with only one edge. So there are  vertices whose degree is one.