#include <bits/stdc++.h>

using namespace std;

#define LL long long

#define INF 0x3f3f3f3f

#define mem(i,j) memset(i,j,sizeof(i))

#define inc(i,l,r) for(int i=l;i<=r;i++)

#define dec(i,r,l) for(int i=r;i>=l;i--)

const int N=+;

const int mod=1e9+;

int n,M;

LL X;

struct NODE {

    int u,v; LL L,C;

    bool operator <(const NODE& p) const {

        return (double)L+(double)X/C > (double)p.L+(double)X/p.C;

    }

};

vector<NODE>G[];

int main()

{

    while(~scanf("%d%d%lld",&n,&M,&X)) {

        inc(i,,n) G[i].clear();

        inc(i,,M) {

            int u,v; LL l,c;

            scanf("%d%d%lld%lld",&u,&v,&l,&c);

            G[u].push_back({u,v,l,c});

            G[v].push_back({v,u,l,c});

        }

        LL ans;

        priority_queue <NODE> q;

        while(!q.empty()) q.pop();

        q.push({,,,INF});

        while(!q.empty()) {

            NODE e=q.top(); q.pop();

            if(e.v==n) {

                ans=e.L+X/e.C; break;

            }

            int len=G[e.v].size()-;

            inc(i,,len) {

                NODE t=G[e.v][i];

                if(t.v==e.u) continue;

                q.push({e.v,t.v,e.L+t.L,min(e.C,t.C)});

            }

        }

        printf("%lld\n",ans);

    }

    return ;

}