#include<bits/stdc++.h>
using namespace std;
template<typename T> inline void read(T& x){
    x=0;int f=1;
    char ch=getchar();
    while(!isdigit(ch)){if(ch=='-') f=~f+1;ch=getchar();}
    while(isdigit(ch)){x=(x<<3)+(x<<1)+(ch^48);ch=getchar();}
    x*=f;
}
template<typename T,typename... Args>inline void read(T& x,Args&... args){
    read(x);
    read(args...);
}
template<typename T>inline void write(T x){
    static int buf[40],top=0;
    if(x<0){putchar('-');x=~x+1;}
    while(x)buf[++top]=x%10,x/=10;
    if(top==0)buf[++top]=0;
    while (top) putchar(buf[top--]^48);
    putchar(' ');
}
template<typename T,typename... Args>inline void write(T x,Args... args){
    write(x);
    write(args...);
}
int n,m,s,a[1010],in[1010],ans;
int used[1010],cnt,tail[1010];
struct node{
	int u,v,next;
}ed[1010];
struct node1{
	int dep,id;
};
void add(int u,int v){
	ed[++cnt].u=u;
	ed[cnt].v=v;
	ed[cnt].next=tail[u];
	tail[u]=cnt;
}
queue<node1>q;
int main(){
	read(n);read(m);
	for(int i=1;i<=n;i++){
		in[i]=-1;
	}
	for(int i=1;i<=m;i++){
		read(s);
		for(int i=1;i<=n;i++){
			used[i]=0;
		}
		for(int j=1;j<=s;j++){
			read(a[j]);
			used[a[j]]++;
		}
		for(int j=a[1];j<=a[s];j++){
			if(in[j]==-1)in[j]=0;
			if(used[j]==0){
				for(int k=1;k<=s;k++){
					add(a[k],j);
					in[j]++;
				}
			}
		}
	}
	for(int i=1;i<=n;i++){
		if(in[i]==0)q.push({1,i});
	}
	while(!q.empty()){
		node1 now=q.front();
		q.pop();
		if(in[now.id]==-1)continue;
		in[now.id]=-1;
		ans=max(ans,now.dep);
		for(int i=tail[now.id];i;i=ed[i].next){
			int to=ed[i].v;
			in[to]--;
			if(in[to]==0){
				q.push({now.dep+1,to});
			}
		}
	}
	write(ans);
	return 0;
}