#include<iostream>

 #include<cstdio>

 #include<algorithm>

 #include<cstring>

 #include<cmath>

 using namespace std;

 const int N=;

 const int M=;

 int cnt,head[N];

 int c[N*],dp[N],q[N*],ans;

 int dfn[N],low[N],tot,fa[N];

 int n,m;

 struct edge{

     int to,nxt;

 }e[M*];

 void add(int u,int v){

     cnt++;

     e[cnt].nxt=head[u];

     e[cnt].to=v;

     head[u]=cnt;

 }

 void getdp(int x,int y){

     int l,r,i,m,p;

     for(m=;y!=x;y=fa[y])c[++m]=dp[y];

     for(c[++m]=dp[x],i=;i<m;i++)c[i+m]=c[i];

     l=r=q[]=;p=m/;

     for(i=;i<=m+p;i++){

         while(l<=r&&i-q[l]>p)l++;

         ans=max(ans,c[i]+c[q[l]]+i-q[l]);

         while(l<=r&&c[i]>=c[q[r]]+i-q[r])r--;

         q[++r]=i;

     }

     for(int i=;i<m;i++)dp[x]=max(dp[x],c[i]+min(i,m-i));

 }

 void Tarjan(int u){

     dfn[u]=low[u]=++tot;

     for(int i=head[u];i;i=e[i].nxt){

         int v=e[i].to;

         if(fa[u]==v)continue;

         if(dfn[v]==){

             fa[v]=u;

             Tarjan(v);

             low[u]=min(low[v],low[u]);

             if(dfn[u]<low[v]){

                 ans=max(ans,dp[v]+dp[u]+);

                 dp[u]=max(dp[u],dp[v]+);

             }

         }else low[u]=min(low[u],dfn[v]);

     }

     for(int i=head[u];i;i=e[i].nxt){

         int v=e[i].to;

         if(fa[v]!=u&&dfn[u]<dfn[v])getdp(u,v);

     }

 }

 int main(){

     scanf("%d%d",&n,&m);

     for(int i=,a,x;i<=m;i++){

         scanf("%d%d",&a,&x);

         for(int j=,y;j<a;j++){

             scanf("%d",&y);

             add(x,y);

             add(y,x);

             x=y;

         }

     }

     Tarjan();

     printf("%d",ans);

     return ;

 }