Minimum spanning tree

Input

The first line contains the number of vertices $n$ and the number of edges $m$ (1 \leq n \leq 100, 1 \leq m \leq 6000). Each of the following $m$ lines contains three integers $a$, $b$, $c$, where $a$ and $b$ are the vertex numbers connected by an edge, and $c$ is the weight of the edge (a positive integer not exceeding $30000$).

Output

Print the weight of the minimum spanning tree.

Examples