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:
# Union-Find部分
def find(x):
    global uf
    if uf[x]<0:
        return x
    else:
        uf[x] = find(uf[x])
        return uf[x]
    
def union(x, y):
    """
    Input: x, y
          x,y are vertex in tree.
    Return: bool
          False: not union. x,y are in same tree.
          True: do union. x,y are not in same tree.
    """
    global uf
    x, y = find(x), find(y)
    if x==y:
        return False
    else:
        if uf[x]<uf[y]:
            x, y = y, x
        uf[x] += uf[y]
        uf[y] = x
        return True
    
V, E = map(int, input().split())
edges = []
for _ in range(E):
    edges.append(tuple(map(int, input().split())))
    
uf = [-1]*V

# クラスカル法の部分
# Union-Findで閉路を作らないようにgreedyに辺を加えているだけ
mst = []
for e in sorted(edges, key=lambda x: x[2]):
    if find(e[0])!=find(e[1]):
        union(e[0], e[1])
        mst.append(e)
print(sum(map(lambda x: x[2], mst)))