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:
class UnionFind:
    # この時点でそれぞれのノードは自分を親としている
    # 初期化時に問題が0の頂点を認めるかに注意すること
    def __init__(self, n):
        self.N = n
        self.parent = [i for i in range(n)]
        self.rank = [0 for _ in range(n)]

    # xの根を返す関数
    def root(self, x):
        visited_nodes = []
        while True:
            p = self.parent[x]
            if p == x:
                # 縮約
                for node in visited_nodes:
                    self.parent[node] = x
                return x
            else:
                visited_nodes.append(x)
                x = p

    # 木の結合を行う。親の配下に入る
    def unite(self, x, y):
        if not self.root(x) == self.root(y):
            if self.rank[x] > self.rank[y]:
                self.parent[self.root(y)] = self.root(x)
            else:
                self.parent[self.root(x)] = self.root(y)
                if self.rank[x] == self.rank[y]:
                    self.rank[self.root(y)] += 1

    def ifSame(self, x, y):
        return self.root(x) == self.root(y)

    # 木の根に到達すまでにたどるノードの配列を返す
    def printDebugInfo(self):
        print([self.root(i) for i in range(self.N)])


V, E = map(int, input().split())
edges = []
for _ in range(E):
    s, t, w = map(int, input().split())
    edges.append([w, s, t])
edges.sort()

tree = UnionFind(V)

weight = 0
counter = 0
for edge in edges:
    if tree.ifSame(edge[1], edge[2]):
        continue
    else:
        tree.unite(edge[1], edge[2])
        weight += edge[0]
        counter += 1
    if counter == V-1:
        break

print(weight)