#include<bits/stdc++.h>
using namespace std;
const int N=1e4,INF=0x3f3f3f3f;
typedef long long LL;
typedef pair<int,int> PII;
int n,m,dis[N],vis[N];
int nex[N],h[N],to[N],c[N],f[N],idx;
void add1(int x,int y,int c1,int f1){
	to[idx++]=y;
	c[idx]=c1;
	f[idx]=f1;
	nex[idx]=h[x];
	h[x]=idx;
	return;
}
void add(int x, int y, int c1, int f1) {
	to[idx] = y;
	c[idx] = c1;
	f[idx] = f1;
	nex[idx] = h[x];
	h[x] = idx++;
}
int dijkstra(int mf){
	memset(dis,0x3f,sizeof(dis));dis[1]=0;
	memset(vis,0,sizeof(vis));
	priority_queue<PII,vector<PII>,greater<PII> > pq;
	pq.push(make_pair(0,1));
	while(!pq.empty()){
		int u=pq.top().second;
		pq.pop();
		if(vis[u])continue;
		vis[u]=1;
		for(int i=h[u];~i;i=nex[i]){
			int v=to[i];
			if(dis[v]>dis[u]+c[i]&&f[i]>=mf){
				dis[v]=dis[u]+c[i];
				pq.push(make_pair(dis[v],v));
			}
		}
	}
	return dis[n];
}
int main() {
	freopen("pump.in","r",stdin);
	freopen("pump.out","w",stdout);
	ios::sync_with_stdio(false);
	cin.tie(0);
	memset(h,-1,sizeof(h));
	cin>>n>>m;
	for(int i=1;i<=m;i++){
		int a,b,c1,f1;
		cin>>a>>b>>c1>>f1;
		add(a,b,c1,f1);
		add(b,a,c1,f1);
	}
	double maxa=0;
	for(int mf=1;mf<=1000;mf++){
		int tc=dijkstra(mf);
		if(tc!=INF){
			double ans=(double)mf/tc;
			if(ans>maxa){
				maxa=ans;
			}
		}
	}
	cout<<(int)(maxa*1000000)<<endl;
	return 0;
}