#include<bits/stdc++.h>
#include<atcoder/all>
using namespace std;
using namespace atcoder;
#define rep(i,n)for (int i = 0; i < int(n); ++i)
#define rrep(i,n)for (int i = int(n)-1; i >= 0; --i)
#define all(x) (x).begin(), (x).end()
#define rall(x) (x).rbegin(), (x).rend()
template<class T> void chmax(T& a, const T& b) {a = max(a, b);}
template<class T> void chmin(T& a, const T& b) {a = min(a, b);}
using ll = long long;
using P = pair<int,int>;
using VI = vector<int>;
using VVI = vector<VI>;
using VL = vector<ll>;
using VVL = vector<VL>;

const unsigned long long INF = 1002003004005006007;
template<class T>
std::vector<unsigned long long> dijkstra(std::vector<std::vector<std::pair<int,T>>>& to, int s=0) {
    struct QueElem {
        int v;
        unsigned long long c;
        bool operator<(const QueElem a) const {return c > a.c;}
        QueElem(int v, unsigned long long c): v(v), c(c) {}
    };
    std::priority_queue<QueElem> q;
    std::vector<unsigned long long> dist(to.size(), INF);
    dist[s] = 0;
    q.emplace(s, 0);
    while(!q.empty()) {
        QueElem qe = q.top(); q.pop();
        int u = qe.v;
        unsigned long long c = qe.c;
        if (c > dist[u]) continue;
        for(auto vc: to[u]) {
            int v = vc.first;
            unsigned long long nc = c + vc.second;
            if (nc < dist[v]) {
                dist[v] = nc;
                q.emplace(v, nc);
            }
        }
    }
    return dist;
}

constexpr int M = 5500;
int main() {
    ios::sync_with_stdio(false);
    cin.tie(0);
    int n, m;
    cin >> n >> m;
    vector<tuple<int,int,int>> es(m);
    rep(i, m) {
        int a, b, c;
        cin >> a >> b >> c, --a, --b;
        es[i] = {a, b, c};
    }
    VI t(n);
    rep(i, n) cin >> t[i];
    vector<vector<P>> to(M * n);
    for(auto [a, b, c]: es) {
        if (a != n - 1) for(int p = 0; p < M; p++) {
            int np = p + t[a];
            if (np >= M) break;
            if (np == 0) continue;
            to[a * M + p].emplace_back(b * M + np, c / np + t[a]);
        }
        if (b != n - 1) for(int p = 0; p < M; p++) {
            int np = p + t[b];
            if (np >= M) break;
            if (np == 0) continue;
            to[b * M + p].emplace_back(a * M + np, c / np + t[b]);
        }
    }
    auto dist = dijkstra(to);
    unsigned long long ans = INF;
    rep(p, M) chmin(ans, dist[M * (n - 1) + p]);
    cout << ans << '\n';
}