Problem: Find the sum of weights of edges of the Minimum Spanning Tree for a given weighted undirected graph G = (V, E).

Constraints

* 1 ≤ |V| ≤ 10,000
* 0 ≤ |E| ≤ 100,000
* 0 ≤ wi ≤ 10,000
* The graph is connected
* There are no parallel edges
* There are no self-loops

Input


|V| |E|
s0 t0 w0
s1 t1 w1
:
s|E|-1 t|E|-1 w|E|-1


, where |V| is the number of vertices and |E| is the number of edges in the graph. The graph vertices are named with the numbers 0, 1,..., |V|-1 respectively.

si and ti represent source and target verticess of i-th edge (undirected) and wi represents the weight of the i-th edge.

Output

Print the sum of the weights of the Minimum Spanning Tree.

Examples

Input

4 6
0 1 2
1 2 1
2 3 1
3 0 1
0 2 3
1 3 5


Output

3


Input

6 9
0 1 1
0 2 3
1 2 1
1 3 7
2 4 1
1 4 3
3 4 1
3 5 1
4 5 6


Output

5

Solution (in PYTHON3):

Solution:
import sys
from operator import itemgetter

def solve():
    n, m = map(int, sys.stdin.readline().split())
    edges = [None] * m

    for i in range(m):
        s, t, w = map(int, sys.stdin.readline().split())
        edges[i] = (s, t, w)

    edges.sort(key=itemgetter(2), reverse=True)

    uf = UnionFind(n)

    ans = 0

    for i in range(n - 1):
        while edges:
            s, t, w = edges.pop()

            if not uf.same(s, t):
                uf.unite(s, t)
                break

        ans += w

    print(ans)

class UnionFind:
    def __init__(self, n):
        self.p = list(range(n))
        self.rank = [0] * n

    def find_root(self, x):
        if x != self.p[x]:
            self.p[x] = self.find_root(self.p[x])

        return self.p[x]

    def same(self, x, y):
        return self.find_root(x) == self.find_root(y)

    def unite(self, x, y):
        u = self.find_root(x)
        v = self.find_root(y)

        if u == v: return

        if self.rank[u] < self.rank[v]:
            self.p[u] = v
        else:
            self.p[v] = u

            if self.rank[u] == self.rank[v]:
                self.rank[u] += 1

if __name__ == '__main__':
    solve()