#include <bits/stdc++.h>
using namespace std;
//#include<atcoder/all>
//using namespace atcoder;
using ll = long long int;
using ull = unsigned long long int;
using ld = long double;
constexpr ll MAX = 2000000000000000000;
constexpr ld PI = 3.14159265358979;
constexpr ll MOD = 0;//2024948111;
ld dotorad(ld K){ return PI * K / 180.0; }
ld radtodo(ld K){ return K * 180.0 / PI; }
mt19937 mt;
void randinit(){ srand((unsigned)time(NULL));mt = mt19937(rand()); }
int main(){
    ll N,M,X;
    cin >> N >> M >> X;
    vector<vector<ll>> G(N),C(N),T(N);
    for(ll i = 0;i < M;i++){
        ll u,v,CC,TT;
        cin >> u >> v >> CC >> TT;
        u--;v--;
        G[u].emplace_back(v);
        C[u].emplace_back(CC);
        T[u].emplace_back(TT);
        G[v].emplace_back(u);
        C[v].emplace_back(CC);
        T[v].emplace_back(TT);
    }
    vector<ll> D(N,MAX);
    priority_queue<tuple<ll,ll,ll>,vector<tuple<ll,ll,ll>>,greater<tuple<ll,ll,ll>>> que;
    que.emplace(0,0,0);
    while(!que.empty()){
        auto [d,nokori,a] = que.top();
        nokori = -nokori;
        que.pop();
        if(D[a] == MAX){
            D[a] = d;
            for(ll i = 0;i < (ll)G[a].size();i++){
                ll b = G[a][i];
                ll c = C[a][i];
                ll t = T[a][i];
                ll newd = d + t + c / X;
                c %= X;
                ll new_nokori = nokori - c;
                if(new_nokori < 0){
                    new_nokori += X;
                    newd += 1;
                }
                que.emplace(newd,-new_nokori,b);
            }
        }
    }
    if(D[N - 1] == MAX) cout << -1 << endl;
    else cout << D[N - 1] << endl;
}