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

const ll INF = 1e18;

int main(){
    ll n, m, x;
    cin >> n >> m >> x;
    vector<vector<pair<int, ll>>> graph(n);
    for (int i = 0; i < m; i++) {
        ll u, v, c, t;
        cin >> u >> v >> c >> t;
        u--, v--;
        graph[u].emplace_back(v, t * x + c);
        graph[v].emplace_back(u, t * x + c);
    }

    priority_queue<pair<ll, int>, vector<pair<ll, int>>, greater<pair<ll, int>>> q;
    vector<ll> cst(n, INF);
    q.push({0, 0});
    cst[0] = 0;

    while (!q.empty()) {
        auto [c, p] = q.top();
        q.pop();
        if (cst[p] != c) continue;

        for(auto [to, cp] : graph[p]){
            if(cst[p] + cp < cst[to]){
                cst[to] = cst[p] + cp;
                q.push({cst[to], to});
            }
        }
    }

    if(cst[n - 1] == INF){
        cout << -1 << endl;
    }else{
        cout << (cst[n-1] + x - 1) / x << endl;
    }
}