/* -*- coding: utf-8 -*-
 *
 * 1449.cc:  No.1449 新プロランド - yukicoder
 */

#include<cstdio>
#include<cstdlib>
#include<cstring>
#include<cmath>
#include<iostream>
#include<string>
#include<vector>
#include<map>
#include<set>
#include<stack>
#include<list>
#include<queue>
#include<deque>
#include<algorithm>
#include<numeric>
#include<utility>
#include<complex>
#include<functional>
 
using namespace std;

/* constant */

const int MAX_N = 100;
const int MAX_C = 1000;
const int INF = 1 << 30;

/* typedef */

typedef pair<int,int> pii;
typedef vector<pii> vpii;

struct Stat {
  int d, i, j;
  Stat() {}
  Stat(int _d, int _i, int _j): d(_d), i(_i), j(_j) {}
  bool operator<(const Stat &s) const { return d > s.d; }
  void print() { printf("Stat(%d,%d,%d)\n", d, i, j); }
};

/* global variables */

vpii nbrs[MAX_N];
int ts[MAX_N], ds[MAX_N][MAX_C + 2];

/* subroutines */

/* main */

int main() {
  int n, m;
  scanf("%d%d", &n, &m);

  int maxc = 0;
  for (int i = 0; i < m; i++) {
    int a, b, c;
    scanf("%d%d%d", &a, &b, &c);
    a--, b--;
    nbrs[a].push_back(pii(b, c));
    nbrs[b].push_back(pii(a, c));
    maxc = max(maxc, c);
  }
  int maxj = maxc + 2;

  for (int i = 0; i < n; i++) scanf("%d", ts + i);

  for (int i = 0; i < n; i++) fill(ds[i], ds[i] + maxj, INF);
  ds[0][0] = 0;

  priority_queue<Stat> q;
  q.push(Stat(0, 0, 0));

  int mind = INF;
  while (! q.empty()) {
    Stat u = q.top(); q.pop();
    //u.print();

    if (ds[u.i][u.j] != u.d) continue;
    if (u.i == n - 1) {
      mind = u.d;
      break;
    }

    int ud = u.d + ts[u.i], vj = min(maxj - 1, u.j + ts[u.i]);
    vpii &nbru = nbrs[u.i];
    for (vpii::iterator vit = nbru.begin(); vit != nbru.end(); vit++) {
      int vi = vit->first, vd = ud + (vit->second / vj);
      if (ds[vi][vj] > vd) {
	ds[vi][vj] = vd;
	q.push(Stat(vd, vi, vj));
      }
    }
  }

  printf("%d\n", mind);
  return 0;
}