#include<bits/stdc++.h>
#define N 1100
#define max(a,b) ((a)>(b)?(a):(b))
#define mem(a,b) memset(a,b,sizeof(a))
#define fsb(a,b,c) for(int a=b;a<=c;a++)
#define fbs(a,b,c) for(int a=b;a>=c;a--)
using namespace std;
int n,m,s,x,into[N*2],vis[N],head[N*2],cnt=0,rk[N*2],ans=0;
int b[N*2],l,r,sz,start;
struct edge{
 int p,nt;
}a[N*N];
template<typename T>inline void rll(T &x){
 x=0;T f=1;char c=getchar();
 while(!isdigit(c))f=c=='-'?-1:f,c=getchar();
 while(isdigit(c))x=x*10+c-'0',c=getchar();
 x*=f;
}
inline void add(int x,int y){
 a[++cnt].p=y;a[cnt].nt=head[x];head[x]=cnt;
}
inline void addb(int x,int y){
 rk[x]=y;b[++r]=x;sz++;
}
int main(){
 rll(n);rll(m);//n车站 m车
 mem(into,0);mem(head,255); 
 fsb(i,1,m){
  rll(s);mem(vis,0);
  fsb(j,1,s){
   rll(x);vis[x]=1;
   start=j==1?x:start;
   into[x]++;add(i+n,x);
  }
  fsb(j,start,x)
   if(!vis[j]){
    into[i+n]++;add(j,i+n);
   }
 }
 l=1;r=0;sz=0;mem(rk,255);
 fsb(i,1,n+m)
  if(into[i]==0)addb(i,0);
 while(sz>0){
  int u=b[l];l++;sz--;
//  printf("%10d %d\n",u,rk[u]);
  for(int t=head[u];t!=-1;t=a[t].nt){
   int v=a[t].p;
   into[v]--;rk[v]=max(rk[v],rk[u]+1);
   if(into[v]==0)addb(v,rk[v]);
  }
 }
 fsb(i,1,n)ans=max(ans,rk[i]);
 printf("%d\n",ans/2+1);
 return 0;
}