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

#define FOR(i, l, r) for(ll i = l; i < r; i++)
#define rep(i, n) FOR(i, 0, n)
#define FORR(i, l, r) for(ll i = r - 1; i >= l; i--)
#define ALL(ar) begin(ar), end(ar)

template <typename T1, typename T2>
inline bool chmax(T1 &a, T2 b) {
    return a < b && (a = b, true);
}
template <typename T1, typename T2>
inline bool chmin(T1 &a, T2 b) {
    return a > b && (a = b, true);
}
template <typename T1, typename T2>
istream &operator>>(istream &is, pair<T1, T2> &p) {
    is >> p.first >> p.second;
    return is;
}
template <typename T1, typename T2>
ostream &operator<<(ostream &os, const pair<T1, T2> &p) {
    os << p.first << ' ' << p.second;
    return os;
}
template <typename T>
istream &operator>>(istream &is, vector<T> &v) {
    for(T &x : v) is >> x;
    return is;
}
template <typename T>
ostream &operator<<(ostream &os, const vector<T> &v) {
    for(size_t i = 0; i < v.size(); i++) os << (i ? " " : "") << v[i];
    return os;
}
//-------------------------------------------------

void solve() {
    ll N, M, X;
    cin >> N >> M >> X;
    vector<vector<pair<ll, ll>>> g(N);
    rep(i, M) {
        ll u, v, c, t;
        cin >> u >> v >> c >> t;
        u--;
        v--;
        c += t * X;
        g[u].emplace_back(v, c);
        g[v].emplace_back(u, c);
    }

    vector<ll> dist(N, 1ll << 60);
    priority_queue<pair<ll, ll>, vector<pair<ll, ll>>, greater<pair<ll, ll>>>
        que;
    que.emplace(0, 0);
    dist[0] = 0;
    while(!que.empty()) {
        auto [d, v] = que.top();
        que.pop();
        if(dist[v] < d) continue;
        for(auto [to, cost] : g[v]) {
            if(chmin(dist[to], d + cost)) que.emplace(d + cost, to);
        }
    }

    if(dist[N - 1] == 1LL << 60) {
        cout << -1 << endl;
    } else {
        cout << (dist[N - 1] + X - 1) / X << endl;
    }
}

int main() {
    int t = 1;
    // cin >> t;
    while(t--) solve();
}