Given a connected, weighted, undirected graph of $n$ vertices and $m$ edges. Find weight of its minimum spanning tree.
_A minimum spanning tree (MST) or minimum weight spanning tree is a subset of the edges of a connected, edge-weighted undirected graph that connects all the vertices together, without any cycles and with the minimum possible total edge weight._
### Input
- The first line contain 2 integers $n, m$.
- The next $m$ lines, each line contains 3 integers $u, v, w$, there is an edge weigh $w$ between $u$ and $v$.
### Output
- Print the weight of the minimum spanning tree.
### Constraints
- $1 \le n, m\le 10^5$.
- $1 \le u, v \le n$.
- $1 \le w \le 10^9$.
### Example
Input:
```
3 3
1 2 1
2 3 2
3 1 3
```
Output:
```
3
```
