#include <iostream>
#define MAXN 5001
#define MAXM 50001
using namespace std;
 
class list
{
public:
	list *next;
	int p;
	list(int tp)
	{
		p=tp;
		next=0;
	}
};
 
class tadjl
{
public:
	list *first,*last;
	void ins(int p)
	{
		if (first)
			last=last->next=new list(p);
		else
			first=last=new list(p);
	}
	tadjl()
	{
		first=last=0;
	}
};
 
int N,M,Ans;
int F[MAXN],G[MAXN];
tadjl adjl[MAXN],rdjl[MAXN];
 
void init()
{
	int i,a,b;
	freopen("cowtraffic.in","r",stdin);
	freopen("cowtraffic.out","w",stdout);
	cin >> N >> M;
	for (i=1;i<=M;i++)
	{
		scanf("%d%d",&a,&b);
		rdjl[a].ins(b);
		adjl[b].ins(a);
	}
}
 
int dynamic1(int i)
{
	int j,A=0;
	list *k;
	if (!adjl[i].first)
		return 1;
	for (k=adjl[i].first;k;k=k->next)
	{
		j=k->p;
		if (F[j]==0)
			F[j]=dynamic1(j);
		A+=F[j];
	}
	return A;
}
 
int dynamic2(int i)
{
	int j,A=0;
	list *k;
	if (!rdjl[i].first)
		return 1;
	for (k=rdjl[i].first;k;k=k->next)
	{
		j=k->p;
		if (G[j]==0)
			G[j]=dynamic2(j);
		A+=G[j];
	}
	return A;
}
 
void solve()
{
	int i,j,V;
	list *k;
	F[N]=dynamic1(N);
	G[1]=dynamic2(1);
	for (i=1;i<N;i++)
	{
		for (k=rdjl[i].first;k;k=k->next)
		{
			j=k->p;
			V=F[i]*G[j];
			if (V>Ans)
				Ans=V;
		}
	}
}
 
int main()
{
	init();
	solve();
	cout << Ans << endl;
	return 0;
}