#include <bits/stdc++.h>
using namespace std;
typedef signed long long ll;

#undef _P
#define _P(...) (void)printf(__VA_ARGS__)
#define FOR(x,to) for(x=0;x<(to);x++)
#define FORR(x,arr) for(auto& x:arr)
#define ITR(x,c) for(__typeof(c.begin()) x=c.begin();x!=c.end();x++)
#define ALL(a) (a.begin()),(a.end())
#define ZERO(a) memset(a,0,sizeof(a))
#define MINUS(a) memset(a,0xff,sizeof(a))
//-------------------------------------------------------

int N,M;
int X[505050];
int miy[505050],may[505050];

void solve() {
	int i,j,k,l,r,x,y; string s;
	
	cin>>N>>M;
	int tmiy=N,tmay=0;
	FOR(i,M) {
		cin>>X[i]>>x;
		miy[i]=may[i]=X[i];
		while(x--) {
			cin>>y;
			miy[i]=min(miy[i],y);
			may[i]=max(may[i],y);
		}
		tmiy=min(tmiy,miy[i]);
		tmay=max(tmay,may[i]);
	}
	int tmix=N,tmax=0;
	FOR(i,M) {
		if(miy[i]<X[i]) tmax=max(tmax,X[i]);
		if(X[i]<may[i]) tmix=min(tmix,X[i]);
	}
	int ret=min((tmax-tmiy)+(tmay-tmiy),(tmay-tmix)+(tmay-tmiy));
	cout<<ret<<endl;
}


int main(int argc,char** argv){
	string s;int i;
	if(argc==1) ios::sync_with_stdio(false), cin.tie(0);
	FOR(i,argc-1) s+=argv[i+1],s+='\n'; FOR(i,s.size()) ungetc(s[s.size()-1-i],stdin);
	cout.tie(0); solve(); return 0;
}