#include<cstdio>
#include<algorithm>
using namespace std;
void MakeSet(int);
int Find(int);
bool Same_Component(int,int);
void Union(int, int);
int Components(int);
struct Path {
    int origin;
    int destiny;
    int cost;
}path[20005];
bool operator < (Path a, Path b) {
    return a.cost < b.cost;
}
int root[1005];
int rank[1005];
int main() {
    int barns,connections;
    int mst = 0;
    scanf("%d %d",&barns,&connections);
    MakeSet(barns);
    for(int i=0;i<connections;i++){
        scanf("%d %d %d",&path[i].origin,&path[i].destiny,&path[i].cost);
        Union(path[i].origin,path[i].destiny);
    }
    if(Components(barns) != 1) printf("-1\n");
    else {
        sort(path,path+connections);
        MakeSet(barns+1);
        for(int i=connections-1;i>=0;i--) {
            if(!Same_Component(path[i].origin,path[i].destiny))
            mst += path[i].cost;
            Union(path[i].origin,path[i].destiny);
        }
        printf("%d\n",mst);
    }
    return 0;
}
void MakeSet(int n) {
    for(int i=0;i<n;i++) {
        root[i] = i;
        rank[i] = 0;
    }
}
int Find(int x) {
    if(x != root[x]) return root[x] = Find(root[x]);
    return x;
}
bool Same_Component(int x, int y) {
    if(Find(x) == Find(y)) return true;
    return false;
}
void Union(int x, int y) {
    int xroot = Find(x);
    int yroot = Find(y);
    if(rank[xroot] > rank[yroot]) root[yroot] = xroot;
    else {
        root[xroot] = yroot;
        if(rank[xroot] == rank[yroot]) rank[yroot]++;
    }
}
int Components(int n) {
    int nComponents = 0;
    for(int i=0;i<n;i++) {
        if(Find(i) == i) {
            root[nComponents] = i;
            nComponents++;
        }
    }
    return nComponents;
}