#include <iostream>
#include <queue>
#include <vector>
using namespace std;
using ll = long long;

int main() {
    ll N, M, X;
    cin >> N >> M >> X;
    vector<vector<pair<ll, ll>>> g(N);
    for (int i = 0; i < M; i++) {
        ll u, v, C, T;
        cin >> u >> v >> C >> T;
        u--;
        v--;
        g[u].push_back({v, C + T * X});
        g[v].push_back({u, C + T * X});
    }
    vector<ll> dist(N, 1e18);
    dist[0] = 0;
    priority_queue<pair<ll, ll>, vector<pair<ll, ll>>, greater<pair<ll, ll>>> pq;
    pq.push({0, 0});
    while (!pq.empty()) {
        auto [d, u] = pq.top();
        pq.pop();
        if (d > dist[u]) continue;
        for (auto [v, w] : g[u]) {
            if (dist[v] > dist[u] + w) {
                dist[v] = dist[u] + w;
                pq.push({dist[v], v});
            }
        }
    }
    if (dist[N - 1] == 1e18) {
        cout << -1 << endl;
    } else {
        cout << (dist[N - 1] + X - 1) / X << endl;
    }
}