#include<bits/stdc++.h>
using namespace std;

#define int long long

#define fs first
#define sd second
using pii=pair<int,int>;
using tii=tuple<int,int,int>;

const int N=2e5+1e3+7;

int n,m;

int dfn[N],dc,use[N];

vector<tii>g[N];

pii fe[N];

vector<int>st;

vector<vector<pii> >cir;

void dfs(int x,int f)
{
	st.push_back(x);
	dfn[x]=++dc;
	for(auto [v,a,b]:g[x])
	{
		if(v==f)
			continue;
		if(!dfn[v])
			fe[v]={a,b},dfs(v,x);
		else if(dfn[v]<dfn[x])
		{
			cir.push_back({{a,b}});
			for(int i=st.size()-1;st[i]!=v;i--)
				cir.back().push_back(fe[st[i]]),use[st[i]]=1;
		}
	}
	if(!use[x])
		cir.push_back({fe[x],fe[x]});
	st.pop_back();
}

pii operator +(const pii &a,const pii &b)
{
	return {a.fs+b.fs,a.sd+b.sd};
}

pii operator -(const pii &a,const pii &b)
{
	return {a.fs-b.fs,a.sd-b.sd};
}

int operator *(const pii &a,const pii &b)
{
	return a.fs*b.sd-a.sd*b.fs;
}

vector<pii>merge(vector<pii> a,vector<pii> b)
{
	pii S=a[0]+b[0];
	vector<pii>ret;
	ret.push_back(S);
	int i=1,j=1;
	while(i<a.size()&&j<b.size())
	{
		if((a[i]-a[i-1])*(b[j]-b[j-1])>=0)
			ret.push_back({a[i]-a[i-1]}),i++;
		else
			ret.push_back({b[j]-b[j-1]}),j++;
	}
	while(i<a.size())
		ret.push_back(a[i]-a[i-1]),i++;
	while(j<b.size())
		ret.push_back(b[j]-b[j-1]),j++;
	for(int i=1;i<ret.size();i++)
		ret[i]=ret[i]+ret[i-1];
	return ret;
}

vector<pii>solve(int l,int r)
{
	if(l==r)
		return cir[l];
	int mid=(l+r)>>1;
	return merge(solve(l,mid),solve(mid+1,r));
}

signed main()
{
	ios::sync_with_stdio(false);
	cin.tie(0);
	cin>>n>>m;
	for(int i=1;i<=m;i++)
	{
		int u,v,a,b;
		cin>>u>>v>>a>>b;
		g[u].push_back({v,a,b});
		g[v].push_back({u,a,b});
	}
	dfs(1,0);
	for(auto &c:cir)
	{
		int sa=0,sb=0;
		for(auto [a,b]:c)
			sa+=a,sb+=b;
		for(auto &[a,b]:c)
			a=sa-a,b=sb-b;
		sort(c.begin(),c.end());
		vector<pii>g;
		for(auto p:c)
		{
			while(g.size()>1&&(p-g[g.size()-2])*(g[g.size()-1]-g[g.size()-2])>=0)
				g.pop_back();
			g.push_back(p);
		}
		c.swap(g);
	}
	auto w=solve(0,cir.size()-1);
	int ans=LONG_LONG_MAX;
	for(auto [a,b]:w)
		ans=min(ans,a*b);
	cout<<ans<<endl;
}
/*
6 7
1 2 1 2
2 3 2 1
3 4 2 3
4 2 3 2 
2 5 1 4
6 5 2 2
6 2 3 1
*/