#include <bits/stdc++.h>

using namespace std;
using ll = long long;

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

int main(){
    cin.tie(nullptr);
    ios_base::sync_with_stdio(false);

    /*
       通った道の集合に対して
       ceil((sum Ci)/X) + sum Ti 時間かかる
       ceil((sum (Ci +Ti*X)) / X) 時間かかる
    */

    ll N, M, X, u, v, C, T;
    cin >> N >> M >> X;
    ll from, alt, d;

    vector<vector<pair<ll, ll>>> E(N);
    for (int i=0; i<M; i++){
        cin >> u >> v >> C >> T;
        u--; v--;
        E[u].push_back({v, C+T*X});
        E[v].push_back({u, C+T*X});
    }

    pq<pair<ll, ll>> que;
    vector<ll> dist(N, 1e18);
    vector<bool> vst(N);

    dist[0] = 0;
    que.push({0, 0});

    while(!que.empty()){
        tie(d, from) = que.top();
        que.pop();
        if (vst[from]) continue;
        vst[from] = 1;
        for (auto [to, C] : E[from]){
            alt = d + C;
            if (alt < dist[to]){
                dist[to] = alt;
                que.push({dist[to], to});
            }
        }
    }

    cout << (dist[N-1] == 1e18 ? -1 : (dist[N-1]+X-1) / X) << endl;

    return 0;
}