#include <bits/stdc++.h>

using namespace std;
using ll = long long;

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

vector<ll> dijkstra(vector<vector<pair<ll, ll>>> &E, ll start){
 
    ll N = E.size();
    ll from, alt, d;

    pq<pair<ll, ll>> que;
    vector<ll> dist(N, 1e18);
    vector<bool> vst(N);
 
    dist[start] = 0;
    que.push({0, start});
 
    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});
            }
        }
    }
 
    return dist;
}

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

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

    vector<ll> dist = dijkstra(E, 0);
    
    cout << (dist[N-1] == 1e18 ? -1 : (dist[N-1]+X-1)/X) << endl;

    return 0;
}