#include<stdio.h>
#include<string.h>
struct gedge{int to,nex;bool bri;
}ge[4000010];
struct tedge{int to,nex;
}te[4010];
int gh[2010],th[2010],s[2010],siz[2010],dfn[2010],low[2010],col[2010],q[2010],f[2010],tot,m;
void gadd(int a,int b){tot++;ge[tot].to=b;ge[tot].nex=gh[a];gh[a]=tot;ge[tot+m].to=a;ge[tot+m].nex=gh[b];gh[b]=tot+m;
}
void tadd(int a,int b){tot++;te[tot].to=b;te[tot].nex=th[a];th[a]=tot;
}
int min(int a,int b){return a<b?a:b;}
int max(int a,int b){return a>b?a:b;}
void bri(int x){ge[x].bri=1;if(x>m)ge[x-m].bri=1;elsege[x+m].bri=1;
}
void tarjan(int fa,int x){tot++;dfn[x]=low[x]=tot;for(int i=gh[x];i;i=ge[i].nex){if(dfn[ge[i].to]==0){tarjan(x,ge[i].to);low[x]=min(low[x],low[ge[i].to]);if(low[ge[i].to]>dfn[x])bri(i);}else if(dfn[ge[i].to]<dfn[x]&&ge[i].to!=fa)low[x]=min(low[x],dfn[ge[i].to]);}
}
void dfs(int x){for(int i=gh[x];i;i=ge[i].nex){if(col[ge[i].to]){if(col[ge[i].to]!=col[x]){tadd(col[x],col[ge[i].to]);tadd(col[ge[i].to],col[x]);}}else if(!ge[i].bri){col[ge[i].to]=col[x];dfs(ge[i].to);}}
}
void dfs(int fa,int x){siz[x]=s[x];for(int i=th[x];i;i=te[i].nex){if(te[i].to!=fa){dfs(x,te[i].to);siz[x]+=siz[te[i].to];}}
}
int main(){int N,n,i,j,k,a,b,ans,res;scanf("%d%d",&n,&m);for(i=0;i<m;i++){scanf("%d%d",&a,&b);gadd(a,b);}tot=0;tarjan(0,1);N=0;tot=0;for(i=1;i<=n;i++){if(col[i]==0){N++;col[i]=N;dfs(i);}}for(i=1;i<=n;i++)s[col[i]]++;ans=0;for(i=1;i<=N;i++){dfs(0,i);res=0;for(j=1;j<=N;j++)res+=s[j]*siz[j];q[0]=0;for(j=th[i];j;j=te[j].nex){q[0]++;q[q[0]]=te[j].to;}memset(f,0,sizeof(f));for(j=1;j<=q[0];j++){for(k=n-s[i];k>=siz[q[j]];k--)f[k]=max(f[k],f[k-siz[q[j]]]+siz[q[j]]);}res+=f[(n-s[i])>>1]*(n-s[i]-f[(n-s[i])>>1]);ans=max(ans,res);}printf("%d",ans);
}