This documentation is automatically generated by online-judge-tools/verification-helper
#define PROBLEM "http://judge.u-aizu.ac.jp/onlinejudge/description.jsp?id=0423"
#include <bits/stdc++.h>
using namespace std;
#define call_from_test
#include "../../graph/dijkstra.cpp"
#undef call_from_test
#ifdef SANITIZE
#define IGNORE
#endif
signed main(){
cin.tie(0);
ios::sync_with_stdio(0);
int n,m;
cin>>n>>m;
vector<int> ts(n),es(n);
for(int i=0;i<n;i++) cin>>ts[i]>>es[i];
Dijkstra<int> G(n+1);
for(int i=0;i<m;i++){
int a,b,c;
cin>>a>>b>>c;
a--;b--;c--;
G.add_edge(b,a,c);
}
for(int i=0;i<n;i++) G.add_edge(n,i,ts[i]);
G.build(n);
long long ans=0;
for(int i=0;i<n;i++) ans+=(long long)G[i]*es[i];
cout<<ans<<endl;
return 0;
}
#line 1 "test/aoj/0423.test.cpp"
#define PROBLEM "http://judge.u-aizu.ac.jp/onlinejudge/description.jsp?id=0423"
#include <bits/stdc++.h>
using namespace std;
#define call_from_test
#line 1 "graph/dijkstra.cpp"
#line 3 "graph/dijkstra.cpp"
using namespace std;
#endif
//BEGIN CUT HERE
template<typename T>
struct Dijkstra{
struct Edge{
int to;
T cost;
Edge(int to,T cost):to(to),cost(cost){}
bool operator<(const Edge &o)const{return cost>o.cost;}
};
vector< vector<Edge> > G;
vector<T> ds;
vector<int> bs;
Dijkstra(int n):G(n){}
void add_edge(int u,int v,T c){
G[u].emplace_back(v,c);
}
void build(int s){
int n=G.size();
ds.assign(n,numeric_limits<T>::max());
bs.assign(n,-1);
priority_queue<Edge> pq;
ds[s]=0;
pq.emplace(s,ds[s]);
while(!pq.empty()){
auto p=pq.top();pq.pop();
int v=p.to;
if(ds[v]<p.cost) continue;
for(auto e:G[v]){
if(ds[e.to]>ds[v]+e.cost){
ds[e.to]=ds[v]+e.cost;
bs[e.to]=v;
pq.emplace(e.to,ds[e.to]);
}
}
}
}
T operator[](int k){return ds[k];}
vector<int> restore(int to){
vector<int> res;
if(bs[to]<0) return res;
while(~to) res.emplace_back(to),to=bs[to];
reverse(res.begin(),res.end());
return res;
}
};
//END CUT HERE
#ifndef call_from_test
signed main(){
return 0;
}
#endif
#line 8 "test/aoj/0423.test.cpp"
#undef call_from_test
#ifdef SANITIZE
#define IGNORE
#endif
signed main(){
cin.tie(0);
ios::sync_with_stdio(0);
int n,m;
cin>>n>>m;
vector<int> ts(n),es(n);
for(int i=0;i<n;i++) cin>>ts[i]>>es[i];
Dijkstra<int> G(n+1);
for(int i=0;i<m;i++){
int a,b,c;
cin>>a>>b>>c;
a--;b--;c--;
G.add_edge(b,a,c);
}
for(int i=0;i<n;i++) G.add_edge(n,i,ts[i]);
G.build(n);
long long ans=0;
for(int i=0;i<n;i++) ans+=(long long)G[i]*es[i];
cout<<ans<<endl;
return 0;
}