#include <bits/stdc++.h>
using namespace std;
#define mk make_pair
#define debug(x) cerr << #x << " = " << x << endl;
#define debugV(x,n) for(int i = 0;i < n;i++) cerr << x[i] << " "; cerr<<endl;
#define rep(i,a,b) for(int i = (int)a;i < (int)b;i++)
#define F first
#define S second
#define pb push_back
typedef pair<int,int> ii;
typedef long long int ll;
const int INF = 0x3f3f3f3f;
const double EPS = 1e-5;

vector < pair<ll,int> > adj[10010];
int n,m;

ll dist[10010];

ll dijkstra(){
    priority_queue <pair <ll,int> > pq;
    rep(i,0,n+2){
        dist[i] = INF;
    }
    dist[1]=0;
    pq.push(mk(-dist[1],1));
    while(!pq.empty()){
        int u = pq.top().S;
        pq.pop();
        if(u == n) return dist[u];
        rep(i,0,adj[u].size()){
            int v = adj[u][i].F;
            ll cost = adj[u][i].S+dist[u];
            if(dist[v] > cost){
                dist[v] = cost;
                pq.push(mk(-dist[v],v));
            }
        }
    }
    return dist[n];
}

int main(){
    int t,a,b,c;
    scanf("%d",&t);
    ll s=0;
    while(t--){
        scanf("%d%d",&n,&m);
        rep(i,0,m){
            scanf("%d%d%d",&a,&b,&c);
            adj[a].pb(mk(b,c));
        }
        s+=dijkstra();
        rep(i,0,n+2)adj[i].clear();
    }
    printf("%lld\n",s);
    return 0;
}