#include <bits/stdc++.h>

using i32 = std::int32_t;
using u32 = std::uint32_t;
using i64 = std::int64_t;
using u64 = std::uint64_t;
using i128 = __int128_t;
using u128 = __uint128_t;
using isize = std::ptrdiff_t;
using usize = std::size_t;

class rep {
    struct Iter {
        usize itr;
        constexpr Iter(const usize pos) noexcept: itr(pos) { }
        constexpr void operator ++ () noexcept { ++itr; }
        constexpr bool operator != (const Iter& other) const noexcept { return itr != other.itr; }
        constexpr usize operator * () const noexcept { return itr; }
    };
    const Iter first, last;
public:
    explicit constexpr rep(const usize first, const usize last) noexcept: first(first), last(std::max(first, last)) { }
    constexpr Iter begin() const noexcept { return first; }
    constexpr Iter end() const noexcept { return last; }
};

template <class T, T Div = 2>
constexpr T INFTY = std::numeric_limits<T>::max() / Div;

template <class T>
bool setmin(T& lhs, const T& rhs) {
    if (lhs > rhs) {
        lhs = rhs;
        return true;
    }
    return false;
}

template <class T>
using Vec = std::vector<T>;

template <class T>
using Heap = std::priority_queue<T, Vec<T>, std::greater<T>>;

constexpr u32 MAX = 1005;

void E_main() {
    usize N, M;
    std::cin >> N >> M;
    Vec<Vec<std::pair<usize, u32>>> graph(N);
    for (auto i: rep(0, M)) {
        usize u, v;
        std::cin >> u >> v;
        u -= 1;
        v -= 1;
        u32 c;
        std::cin >> c;
        graph[u].emplace_back(v, c);
        graph[v].emplace_back(u, c);
    }
    Vec<u32> T(N);
    for (auto& x: T) {
        std::cin >> x;
    }
    using State = std::tuple<u32, usize, usize>;
    Heap<State> que;
    Vec<Vec<u32>> dist(N, Vec<u32>(MAX + 1, INFTY<u32>));
    const auto push = [&](const usize u, const usize l, const u32 d) {
        if (setmin(dist[u][l], d)) {
            que.emplace(d, u, l);
        }
    };
    push(0, 0, 0);
    while (!que.empty()) {
        const auto [d, u, l] = que.top();
        que.pop();
        if (d > dist[u][l]) {
            continue;
        }
        const auto nl = std::min<usize>(l + T[u], MAX);
        for (const auto [v, c]: graph[u]) {
            push(v, nl, d + T[u] + c / nl);
        }
    }
    std::cout << *std::min_element(dist[N - 1].begin(), dist[N - 1].end()) << '\n';
    return;
}

int main() {
    std::ios_base::sync_with_stdio(false);
#ifndef LOCAL
    std::cin.tie(nullptr);
#endif
    E_main();
    return 0;
}