#include <cstdio>
#include <cstring>
#include <cmath>
#include <iostream>
#include <algorithm>
#include <vector>
#include <stack>
#include <sstream>
#include <map>
#include <set>
#include <string>
using namespace std;
typedef long long ll;

#define mem(a,b) memset(a,b,sizeof(a))

vector<int>v[100005];

map<int,int>mp1,mp2;

int t[200005];
int x[3005][3005];
int n,m;

int find(int x)
{
    if(x==t[x])return x;
    return t[x]=find(t[x]);
}

void check(int x,int y)
{
    int fx=find(x);
    int fy=find(y);
    if(fx!=fy)t[fx]=fy;
}

int main()
{
    int a,b,c;
    while (cin >> n >> m)
    {
        mem(x,0);
        mp1.clear();
        mp2.clear();
        for(int i=1;i<=n;++i)
{
 v[i].clear();
}
        for(int i=1;i<=n;++i) t[i]=i;
        for(int i=1;i<=m;++i)
        {
            scanf("%d %d %d",&a,&b,&c);
            x[a][b]+=c;
            x[b][a]+=c;
            check(a,b);
        }
        for(int i=1;i<=n;++i)
        {
            for(int j=1;j<=n;++j)
            {
                if(i==j) continue;;
                mp1[i]+=x[i][j];
            }
        }
        for(int i=1;i<=n;++i)
        {
            if(mp2[find(i)]) mp2[find(i)]=min(mp2[find(i)],mp1[i]);
            else mp2[find(i)]=mp1[i];
            v[find(i)].push_back(i);
        }
        ll sum=0;
        for(int i=1;i<=n;++i)
        {
            if(find(i)==i) if(v[i].size()>1) sum+=mp2[i];
        }
        cout << sum << endl;
    }
    return 0;
}