#include <bits/stdc++.h>
using namespace std;
// #define int long long
using ll=long long;
using vi=vector<int>;
using vl=vector<long long>;
using pii=pair<int,int>;
using pll=pair<long long,long long>;
#define ITR(i,c) for(auto i=begin(c);i!=end(c);++i)
#define FORE(x,c) for(auto &x:c)
#define REPF(i,a,n) for(int i=a,i##len=(int)(n);i<i##len;++i)
#define REP(i,n) REPF(i,0,n)
#define REPR(i,n) for(int i=(int)(n);i>=0;--i)
#define REPW(i,n) for(i=0;i<(int)(n);++i)
#define ALL(c) begin(c),end(c)
#define RALL(c) rbegin(c),rend(c)   // c++14
#define SZ(c) ((int)c.size())
#define EXIST(c,x) (c.find(x)!=end(c))
#define OUTOFRANGE(y,x,h,w) (y<0||x<0||y>=h||x>=w)
#define dump(...)
const int DX[9]={0,1,0,-1,1,1,-1,-1,0},DY[9]={-1,0,1,0,-1,1,1,-1,0};
#define INF (1001001001)
#define INFLL (1001001001001001001ll)
template<class T> ostream& operator << (ostream &os,const vector<T> &v) {
    ITR(i,v) os << *i << (i==end(v)-1 ? "" : "\n"); return os; }
template<class T> istream& operator >> (istream &is,vector<T> &v) {
    ITR(i,v) is >> * i; return is; }
template<class T> istream& operator >> (istream &is, pair<T,T> &p) {
        is >> p.first >> p.second; return is; }
template<class T>bool chmax(T &a,const T &b){if(a<b){a=b;return 1;}return 0;}
template<class T>bool chmin(T &a,const T &b){if(b<a){a=b;return 1;}return 0;}
//------------------------------------------------------------------------------
struct before_main_function {
    before_main_function() {
        #ifdef int
            #undef INF
            #define INF INFLL
            #define stoi stoll
        #endif
        cin.tie(0);ios::sync_with_stdio(false);
        cout<<setprecision(15)<<fixed;
    }
} before_main_function;
//------------------------------------------------------------------------------

void solve(int N,int M,int L) {
    struct edge{
        int to;
        int left;
        int dist;
        int thief;
    };
    vector<vector<vector<edge>>> g(N,vector<vector<edge>>(110));
    REP(i,M) {
        int a,b,d,e;
        cin>>a>>b>>d>>e;
        REP(j,110) {
            g[a-1][j].push_back(edge{b-1,j,d,e});  // ????????????
            if(j-d>=0) g[a-1][j].push_back(edge{b-1,j-d,d,e});  // ??????
        }
        REP(j,110) {
            g[b-1][j].push_back(edge{a-1,j,d,e});  // ????????????
            if(j-d>=0) g[b-1][j].push_back(edge{a-1,j-d,d,e});  // ??????
        }
    }
    vector<vector<int>> dp(N,vector<int>(110,INF));
    dp[0][L]=0;
    priority_queue<pair<int,pii>,vector<pair<int,pii>>,greater<pair<int,pii>>> pq;
    pq.push({0,{0,L}});
    while(!pq.empty()) {
        int y=pq.top().second.first;
        int z=pq.top().second.second;
        pq.pop();
        FORE(e,g[y][z]) {
            if(z==e.left) {
                if(dp[e.to][e.left]>dp[y][z]+e.thief) {
                    dp[e.to][e.left]=dp[y][z]+e.thief;
                    pq.push({dp[e.to][e.left],{e.to,e.left}});
                }
            }
            else {
                if(dp[e.to][e.left]>dp[y][z]) {
                    dp[e.to][e.left]=dp[y][z];
                    pq.push({dp[e.to][e.left],{e.to,e.left}});
                }
            }
        }
    }
    int ans=INF;
    REP(i,110) chmin(ans,dp[N-1][i]);
    cout<<ans<<endl;
}
signed main() {
    while(1) {
        int N,M,L;
        cin>>N>>M>>L;
        if(N+M+L==0) break;
        solve(N,M,L);
    }
    return 0;
}

Measured memory_bytes: 36824