Problem:
Minimum Spanning Tree

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

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.

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

Sample Input 1

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

Sample Output 1

3

Sample Input 2

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

Sample Output 2

5

Solution in Python3 (judge verdict: Accepted)

ii = lambda : int(input())
mi = lambda : map(int,input().split())
li = lambda : list(map(int,input().split()))

v,e = mi()

path = []

for i in range(e):
    a = li()
    path.append([a[2], a[0], a[1]])

path.sort()

class UnionFind:
    def __init__(self,n):
        self.n = n
        self.d = [-1] * n

    def find(self, x):
        if(self.d[x] < 0):
            return x
        self.d[x] = self.find(self.d[x])
        return self.d[x]

    def union(self, x, y):
        x = self.find(x)
        y = self.find(y)
        if(x == y):
            return False
        if(self.d[x] > self.d[y]):
            x, y = y, x
        self.d[x] += self.d[y]
        self.d[y] = x
        return True

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

    def size(self,x):
        return -self.d[self.find(x)]

uf = UnionFind(v)

ans = 0
for i in path:
    w = i[0]
    s = i[1]
    t = i[2]
    if uf.same(s,t):
        pass
    else:
        uf.union(s,t)
        ans += w


print(ans)