#include<bits/stdc++.h>
using namespace std;
const int N=1005;
int n,m,head[N],cnt;
struct edge{
	int v,w,next,f;
}e[N<<1];
void addedge(int u,int v,int w,int f){
	e[++cnt].v=v;
	e[cnt].w=w;
	e[cnt].f=f;
	e[cnt].next=head[u];
	head[u]=cnt;
}
int ans;
int vis[N],dis[N];
struct node{
	int u,d;
	bool operator<(const node&r) const{
		return d>r.d;
	}
};
int dij(int u,int en,int li){
	memset(vis,0,sizeof(vis));
	for(int i = 1;i<=n;i++) dis[i]=10000000;
	priority_queue<node> q;
	q.push(node{u,0}); dis[u]=0;
	while(!q.empty()){
		int u = q.top().u; q.pop();
		if(vis[u])continue; vis[u]=1;
		for(int i = head[u];i;i=e[i].next){
			int v=e[i].v;
			if(dis[v]>dis[u]+e[i].w&&e[i].f>=li){
				dis[v]=dis[u]+e[i].w;
				q.push(node{v,dis[v]});
			}
		}
	} //cout<<dis[en]<<endl;
	return dis[en];
}
int main(){
	freopen("pump.in","r",stdin);
	freopen("pump.out","w",stdout);
	scanf("%d%d",&n,&m);
	for(int i = 1;i<=m;i++){
		int u,v,w,f; scanf("%d%d%d%d",&u,&v,&w,&f);
		addedge(u,v,w,f); addedge(v,u,w,f);
	}
	for(int u = 1;u<=n;u++){
		for(int i = head[u];i;i=e[i].next){
			int v=e[i].v;
			if(v<u) continue;
			int k1=dij(u,1,e[i].f)+dij(v,n,e[i].f)+e[i].w;
			int k2=dij(v,1,e[i].f)+dij(u,n,e[i].f)+e[i].w; //cout<<e[i].f<<" "<<min(k1,k2)<<endl;
			ans=max(ans,(int)(1000000*e[i].f/min(k1,k2)));
		}
	}
	printf("%d",ans);
	return 0;
}