#include <bits/stdc++.h>
using namespace std;
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];
  }
  int MAX = 30001;
  vector<vector<int>> dp(MAX + 1, vector<int>(N, INF));
  dp[0][0] = 0;
  for (int i = 0; i <= MAX; i++){
    for (int j = 0; j < N; j++){
      if (dp[i][j] != INF){
        for (auto P : E[j]){
          int w = P.second;
          int i2 = i + T[j];
          if (i2 <= MAX){
            int t = dp[i][j] + T[j] + P.first / (i + T[j]);
            dp[i2][w] = min(dp[i2][w], t);
          }
        }
      }
    }
  }
  int ans = INF;
  for (int i = 0; i <= MAX; i++){
    ans = min(ans, dp[i][N - 1]);
  }
  cout << ans << endl;
}