#include <bits/stdc++.h>
using namespace std;
const int MAX = 1200;
const int INF = 1000000000;
int main(){
  int N, M;
  cin >> N >> M;
  vector<vector<pair<int, int>>> E(N);
  for (int i = 0; i < M; i++){
    int A, B, C;
    cin >> A >> B >> C;
    A--;
    B--;
    E[A].push_back(make_pair(C, B));
    E[B].push_back(make_pair(C, A));
  }
  vector<int> T(N);
  for (int i = 0; i < N; i++){
    cin >> T[i];
  }
  vector<vector<int>> d(N, vector<int>(MAX + 1, INF));
  priority_queue<tuple<int, int, int>, vector<tuple<int, int, int>>, greater<tuple<int, int, int>>> pq;
  pq.push(make_tuple(T[0], 0, T[0]));
  while (!pq.empty()){
    int dd = get<0>(pq.top());
    int v = get<1>(pq.top());
    int c = get<2>(pq.top());
    pq.pop();
    if (d[v][c] == INF){
      d[v][c] = dd;
      for (auto P : E[v]){
        int w = P.second;
        int c2 = min(c + T[w], MAX);
        if (d[w][c2] == INF){
          pq.push(make_tuple(dd + P.first / c2 + T[w], w, c2));
        }
      }
    }
  }
  int ans = INF;
  for (int i = 0; i <= MAX; i++){
    ans = min(ans, d[N - 1][i]);
  }
  cout << ans << endl;
}