Minimum Spanning Tree

You are given an undirected weighted graph. Among all subgraphs that connect every vertex, find a tree whose total edge weight is as small as possible.

Such a tree is called a minimum spanning tree.

The first line contains the number of vertices V and the number of edges E.

• 1 <= V <= 10,000
• 1 <= E <= 100,000

Each of the next E lines contains three integers A, B, and C, describing one edge. It means that vertex A and vertex B are connected by an edge with weight C.

• Vertices are numbered from 1 to V.
• C may be negative, and |C| <= 1,000,000.
• There is always a path between any two vertices.
• The total weight of the minimum spanning tree is within the range of a signed 32-bit integer.

Print the total weight of the minimum spanning tree on one line.