#include <bits/stdc++.h>
#include <list>
#define len(x) (int) x.size()
#define all(x) x.begin(), x.end()
#define ll long long
#define ull unsigned long long
#define ld long double
#define start time_t res1 = time(NULL)
#define finish              \
  time_t res2 = time(NULL); \
  cerr << res2 - res1 << '\n'
const long long mod1 = 1e9 + 7;
const long long mod2 = 998244353;
const long long MAXLL = 9223372036854775807;
const long long MAXINT = 2147483647;

using namespace std;

void print(vector<pair<int, int>> a);

void print(vector<int> a);

void print(vector<vector<int>> a);

void print(vector<vector<char>> a);

void print(vector<char> a);

// #define mtask
 #define int ll

int n, m, p;
vector<vector<vector<ld>>> g;
vector<vector<ld>> dist;

void solve(){
    cin >> n >> m >> p;
    g.resize(n);
    dist.resize(n, vector<ld>(p + 1, -1e9));
    dist[0][0] = 0;
    for(int i = 0; i < m; ++i){
        ld u, v, d, s;
        cin >> u >> v >> d >> s;
        --u, --v;
        g[(int)u].push_back({v, d, s});
        g[(int)v].push_back({u, d, s});
    }
    for(int i = 0; i < n; ++i){
        ld mmax = 0;
        for(auto x : g[i]) mmax = max(mmax, (ld)x[2] / (ld)x[1]);
        g[i].push_back({(ld)i, 1, mmax});
    }
    vector<pair<int, int>> bfs(n, {1e9, 0});
    bfs[0] = {0, 0};
    set<pair<int, int>> q;
    q.insert({0, 0});
    while(len(q)){
        auto [d, cur] = *q.begin();
        q.erase(q.begin());
        for(auto x : g[cur]){
            if(bfs[x[0]].first > bfs[cur].first + x[1]){
                bfs[x[0]].first = d + x[1];
                bfs[x[0]].second = bfs[cur].second + x[2];
                q.insert({bfs[x[0]].first, x[0]});
            }
            else if(bfs[x[0]].first == bfs[cur].first + x[1] && bfs[x[0]].second < bfs[cur].second + x[2]){
                bfs[x[0]].first = d + x[1];
                bfs[x[0]].second = bfs[cur].second + x[2];
                q.insert({bfs[x[0]].first, x[0]});
            }
        }
    }
    ld mmax = 0;
    //print(bfs);
    for(int cur = 0; cur < n; ++cur){
        for(auto x : g[cur]){
            int ind = cur;
            if(bfs[cur].first > bfs[x[0]].first){
                ind = x[0];
            }
            else if(bfs[cur].first == bfs[x[0]].first && bfs[cur].second < bfs[x[0]].second) ind = x[0];
            if(2 * bfs[ind].first > p) continue;
            ld cur = (p - 2 * bfs[ind].first) * x[2] / x[1];
            mmax = max(mmax, cur + 2 * bfs[ind].second);
        }
    }
    cout << mmax << '\n';
}

signed main() {
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);
    cout.precision(40);
#ifdef LOCAL
    freopen("input.txt", "r", stdin);
    freopen("output.txt", "w", stdout);
#endif
#ifdef mtask
    int t;
  cin >> t;
  while (t--)
#endif
    solve();
}

void print(vector<pair<int, int>> a) {
    for (int i = 0; i < len(a); ++i) {
        cout << a[i].first << ' ' << a[i].second << '\n';
    }
}

void print(vector<int> a) {
    for (int i = 0; i < len(a); ++i) {
        cout << a[i] << ' ';
    }
    cout << '\n';
}

void print(vector<vector<int>> a) {
    for (int i = 0; i < len(a); ++i) {
        print(a[i]);
    }
}

void print(vector<char> a) {
    for (int i = 0; i < len(a); ++i) {
        cout << a[i];
    }
    cout << '\n';
}

#ifndef int

void print(vector<ll> a) {
    for (int i = 0; i < len(a); ++i) {
        cout << a[i] << ' ';
    }
    cout << '\n';
}

#endif

void print(vector<vector<char> > a) {
    for (int i = 0; i < len(a); ++i) {
        print(a[i]);
    }
}