#include <bits/stdc++.h>
using namespace std;

struct iofast_t {
    iofast_t() {
        ios::sync_with_stdio(false);
        cin.tie(nullptr);
    }
} iofast;

struct uns_t {} uns;
template <typename Element, typename Head, typename ...Args>
auto vec(Element init, Head arg, Args ...args) {
    if constexpr (sizeof...(Args) == 0) return std::vector(arg, init);
    else return std::vector(arg, vec(init, args...));
}
template <typename Element, typename Head, typename ...Args>
auto vec(uns_t, Head arg, Args ...args) {
    return vec(Element(), arg, args...);
}

template <typename T, typename Compare = less<T>>
T &chmin(T &l, T r, Compare &&f = less<T>()) { return l = min(l, r, f); }
template <typename T, typename Compare = less<T>>
T &chmax(T &l, T r, Compare &&f = less<T>()) { return l = max(l, r, f); }

template <typename T>
using pqueue = priority_queue<T, vector<T>, greater<T>>;

int main() {
    constexpr auto inf = INT_MAX / 2;
    constexpr auto lim = 1001;

    int n, m; cin >> n >> m;
    auto g = vec<tuple<int, int>>(uns, n, 0);
    for (int i = 0; i < m; ++i) {
        int a, b, c; cin >> a >> b >> c; --a; --b;
        g[a].push_back({ b, c });
        g[b].push_back({ a, c });
    }
    auto t = vec<int>(uns, n);
    for (auto &e : t) cin >> e;

    pqueue<tuple<int, int, int>> que;
    auto dist = vec<int>(inf, n, lim + 1);

    que.push({ 0, 0, 0 });
    dist[0][0] = 0;
    while (!empty(que)) {
        auto [d, v, sum] = que.top(); que.pop();

        if (dist[v][sum] < d) {
            continue;
        }

        for (auto [u, c] : g[v]) {
            int p = sum + t[v];
            c /= p; chmin(p, lim);

            if (dist[u][p] <= d + t[v] + c) {
                continue;
            }
            dist[u][p] = d + t[v] + c;

            que.push({ dist[u][p], u, p });
        }
    }

    cout << *min_element(begin(dist[n - 1]), end(dist[n - 1])) << endl;
}