#include <cstdio>

#include <cstring>

#include <algorithm>

using namespace std;

const int maxn = 1e5+;

const int maxm = 4e5+;

int N,M;

struct Edge{

    int to,next;

}edge[maxm];

int NE,head[maxn],mem[maxn],chd[maxn];

long long ans;

int add_edge(int u,int v)

{

    edge[NE].to = v;

    edge[NE].next = head[u];

    head[u] = NE++;

    chd[u]++;

    edge[NE].to = u;

    edge[NE].next = head[v];

    head[v] = NE++;

    chd[v]++;

}

long long dfs(int u)

{

    if(mem[u] != -) {ans = max((long long)chd[u]*mem[u],ans);return mem[u];}

    mem[u] = ;

    for(int i=head[u];~i;i=edge[i].next)

    {

        int v = edge[i].to;

        if(v > u) continue;

        mem[u] = max((long long)mem[u],dfs(v)+);

    }

    ans = max((long long)mem[u] * chd[u],ans);

    return mem[u];

}

int main()

{

    scanf("%d%d",&N,&M);

    memset(head,-,sizeof head);

    memset(mem,-,sizeof mem);

    for(int i=,u,v;i<M;i++)

    {

        scanf("%d%d",&u,&v);

        add_edge(u,v);

    }

    for(int i=;i<=N;i++) dfs(i);

    printf("%I64d\n",ans);

}