#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;
struct edge
{
    int to,cost;
    edge(int a,int b)
    {
        to=a;
        cost=b;
    }
};
vector<edge> point[10001];
long D[10001];
long INF = 100000001;
long minuse[10001];
int main()
{
    long n,m;
    cin>>n>>m;
    int a,b,c;
    for(long i=0;i<m;i++)
    {
        cin>>a>>b>>c;
        point[a].push_back(edge(b,c));
        point[b].push_back(edge(a,c));
    }
    for(int i=1;i<=n;i++)
        D[i]=INF;
    D[0]=D[1]=0;
    for(int i=1;i<=n;i++)
        minuse[i]=INF;
    minuse[0]=minuse[1]=0;
    vector<int> s;
    vector<int> q;
    for(int i=1;i<=n;i++)
        q.push_back(i);
    long minflag=INF;
    int v;
    while(q.size()!=0)
    {
        minflag=INF;
        for(int i=0;i<q.size();i++)
        {
            if(D[q[i]]<minflag)
            {
                minflag=D[q[i]];
                v=i;
            }
        }
        s.push_back(q[v]);
        int j=q[v];
        q.erase(q.begin()+v);
        for(long i=0;i<point[j].size();i++)
        {
            if(D[point[j][i].to]>D[j]+point[j][i].cost)
            {
                D[point[j][i].to]=D[j]+point[j][i].cost;
                minuse[point[j][i].to]=point[j][i].cost;
            }
            else
                if(D[point[j][i].to]==D[j]+point[j][i].cost&&minuse[point[j][i].to]>point[j][i].cost)
                    minuse[point[j][i].to]=point[j][i].cost;
                else;
        }
    }
    long pp=0;
    for(int i=1;i<=n;i++){
        pp = pp+minuse[i];
    }
    cout<<pp;
    return 0;
}