#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


void solve(){
    int n, m, p;
    cin >> n >> m >> p;
   
        vector<vector<vector<ld>>> g;
        vector<vector<ld>> dist;
        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});
        }
        for(int T = 0; T < p; ++T) {
            for(int cur = 0; cur < n; ++cur){
                for (auto x: g[cur]) {
                    int newT = T + x[1];
                    if (newT > p) continue;
                    if (dist[(int) x[0]][newT] < dist[cur][T] + (ld) x[2]) {
                        dist[(int) x[0]][newT] = dist[cur][T] + (ld) x[2];
                    }
                }
            }
        }
        cout << dist[0][p] << '\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]);
    }
}