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

#define int ll
#define fast_io cin.tie(0)->sync_with_stdio(0);
#define endl '\n'
typedef long long ll;


int32_t main() {
	fast_io;

    int n, m; cin >> n >> m;
    using T = array<int, 4>;
    vector<T> edges;
    vector<vector<array<int, 3>>> g(n);
    for (int i = 0; i < m; i++) {
        int u, v, w, t; cin >> u >> v >> w >> t; --u, --v;
        edges.push_back({u, v, w, t});
        g[u].push_back({v, w, i});
        g[v].push_back({u, w, i});
    }
    vector<int> state(m);

    vector<int> dist(n);
    vector<pair<int, int>> par(n);
    const int INF = 1e18;
    auto dijkstra = [&] (int s) {
        fill(dist.begin(), dist.end(), INF);
        dist[s] = 0;
        priority_queue<pair<int, int>, vector<pair<int, int>>, greater<pair<int, int>>> pq;
        pq.emplace(dist[s], s);
        while (pq.size()) {
            auto [d, u] = pq.top();
            pq.pop();
            if (d > dist[u]) continue;
            for (auto [v, w, i] : g[u]) {
                if (dist[v] > dist[u] + w) {
                    dist[v] = dist[u] + w;
                    par[v] = {u, i};
                    pq.emplace(dist[v], v);
                }
            }
        }
    };
    dijkstra(0);
    int ans = dist[n - 1];
    int at = n - 1;
    set<pair<int, int>> st;
    while (at != 0) {
        state[par[at].second]++;
        st.insert({par[at].first, at});
        at = par[at].first;
    }

    for (int i = 0; i < n; i++) g[i].clear();
    for (int i = 0; i < m; i++) {
        auto [u, v, w, t] = edges[i];
        if (state[i]) {
            if (st.count({u, v})) {
                g[v].push_back({u, -w, i});
            } else {
                g[u].push_back({v, -w, i});
            }
            g[u].push_back({v, t, i});
            g[v].push_back({u, t, i});
        } else {
            g[u].push_back({v, w, i});
            g[v].push_back({u, w, i});
        }
    }

    fill(dist.begin(), dist.end(), INF);
    dist[0] = 0;
    deque<int> dq;
    vector<int> in(n);
    in[0] = true;
    dq.push_front(0);
    while (dq.size()) {
        int u = dq.front(); dq.pop_front();
        in[u] = false;
        for (auto [v, w, _] : g[u]) {
            if (dist[v] > dist[u] + w) {
                dist[v] = dist[u] + w;
                if (in[v]) continue;
                if (dq.size() && dist[dq.front()] < dist[v]) dq.push_back(v);
                else dq.push_front(v);
                in[v] = true;
            }
        }
    }

    ans += dist[n - 1];

    cout << ans << endl;
}