Score : 1000 points
You are given a tree with N vertices. The vertices are numbered 0 through N-1, and the edges are numbered 1 through N-1. Edge i connects Vertex x_i and y_i, and has a value a_i. You can perform the following operation any number of times:
Your objective is to have a_e = 0 for all edges e. Find the minimum number of operations required to achieve it.
Input is given from Standard Input in the following format:
N x_1 y_1 a_1 x_2 y_2 a_2 : x_{N-1} y_{N-1} a_{N-1}
Find the minimum number of operations required to achieve the objective.
5 0 1 1 0 2 3 0 3 6 3 4 4
3
The objective can be achieved in three operations, as follows:
2 1 0 0
0