wgraph<pair<int,int>>g;
ll@n,@m,@x;
int u[m],v[];
pair<int,int>ab[];
rep(i,m){
	rd(u[i]--,v[i]--,ab[i].first,ab[i].second);
}
g.setEdge(n,m,u,v,ab);
DijkstraHeap<ll>h;
h.malloc(n);
ll ok=-1,ng=1d9+1;
while(ok+1<ng){
	ll z=ok+ng>>1;
	h.init(n);
	h.change(0,0);
	while(h.size){
		ll i=h.pop();
		rep(j,g.es[i]){
			if(g.cost[i][j].second>=z){
				h.change(g.edge[i][j],h.val[i]+g.cost[i][j].first);
			}
		}
	}
	if(h.visited[n-1]&&h.val[n-1]<=x){
		ok=z;
	}else{
		ng=z;
	}
}
wt(ok);