#pragma GCC optimize("O3")
#include<bits/stdc++.h> 
using namespace std;
using ll=long long;
using P=pair<ll,ll>;
template<class T> using V=vector<T>; 
#define fi first
#define se second
#define all(v) (v).begin(),(v).end()
const ll inf=(1e18);
//const ll mod=998244353;
const ll mod=1000000007;
const vector<int> dy={-1,0,1,0},dx={0,-1,0,1};
ll GCD(ll a,ll b) {return b ? GCD(b,a%b):a;}
ll LCM(ll c,ll d){return c/GCD(c,d)*d;}
//struct __INIT{__INIT(){cin.tie(0);ios::sync_with_stdio(false);cout<<fixed<<setprecision(20);}} __init;
template<class T> bool chmax(T &a, const T &b) { if (a<b) { a=b; return 1; } return 0; }
template<class T> bool chmin(T &a, const T &b) { if (a>b) { a=b; return 1; } return 0; }
template<class T>void debag(const vector<T> &a){cerr<<"debag :";for(auto v:a)cerr<<v<<" ";cerr<<"\n";}
template<class T>void print(const vector<T> &a){for(auto v:a)cout<<v<<" ";cout<<"\n";}
struct edge{
    int to;
    ll cost;
    edge(int to,ll cost):to(to),cost(cost){}
};
const ll ma=1005;
using pp=pair<ll,P>;
int main(){
    int n,m;
    cin>>n>>m;
    V<V<edge>> g(n);
    for(int i=0;i<m;i++){
         ll a,b,c;
         cin>>a>>b>>c;
         --a;--b;
         g[a].emplace_back(b,c);
         g[b].emplace_back(a,c);
    }
    V<ll> t(n);
    for(int i=0;i<n;i++)cin>>t[i];
    V<V<ll>> dp(n+5,V<ll>(1010,inf));
    dp[0][0]=0;
    priority_queue<pp,V<pp>,greater<pp>> pq;
    pq.emplace(0,P(0,0));
    while(pq.size()){
        ll res=pq.top().fi,tim=pq.top().se.se;
        int cur=pq.top().se.fi;
        pq.pop();
        if(cur==n-1){
              cout<<res<<"\n";
              return 0;
        }
        if(res>dp[cur][tim])continue;
        tim+=t[cur];
        res+=t[cur];
        chmin(tim,ma);
        for(edge &e:g[cur]){
              if(chmin(dp[e.to][tim],res+e.cost/tim)){
                   pq.emplace(dp[e.to][tim],P(e.to,tim));
              }
        }
    }
}