#include <cstdio>
#include <vector>
#include <algorithm>
#include <unordered_set>
#include <cstring>
#include <utility>
using namespace std;
typedef pair<int,int> ii;
int l,r,total,run,lim;
bool st2=true; //its actually st1 and 2 but who cares
vector<int> v[500005];
vector<ii> range;
struct node{
int s,e,m,len;
bool blocked,split;
node *l,*r;
node(int _s,int _e){
s=_s,e=_e,m=(s+e)>>1; //going to lazily build the ST
blocked =false;
split=false;
}
void update(int i,int j){
if (i==s && j==e){
blocked=true;
}
else{
if (!split){
split=true;
l=new node(s,m);
r=new node(m+1,e);
}
if (j<=m) l->update(i,j);
else if (i>m) r->update(i,j);
else l->update(i,m),r->update(m+1,j);
}
}
int query(int i,int j){
if (blocked) return e-s+1;
else if (split) return l->query(i,m)+r->query(m+1,j);
else return 0;
}
}*root;
inline int read(){
int x=0;
char c=getchar_unlocked();
while ('0'<=c && c<='9'){
x=(x<<3)+(x<<1)+c-'0';
c=getchar_unlocked();
}
return x;
}
int main(){
int a,b;
//freopen("meow","r",stdin);
l=read();
r=read();
root=new node(1,l);
for (int x=0;x<r;x++){
a=read();
if (a!=1) st2=false;
for (int y=0;y<a;y++){
b=read();
v[x].push_back(b);
}
}
if (st2){
int _max=0;
for (int x=0;x<r;x++) _max=max(_max,v[x][0]);
printf("%d\n",max(_max*2-l,0));
}
else {
vector<ii>::iterator it;
for (int x=0;x<r;x++){
if (v[x].size()==0) continue;
range.clear();
total=0;
run=0;
for (vector<int>::iterator it=v[x].begin();it!=v[x].end();it++){
total+=*it;
}
total=l-total;
range.push_back(ii(1,total));
for (vector<int>::iterator it=v[x].begin();it!=v[x].end();it++){
run+=*it;
range.push_back(ii(run+1,total));
}
int run=1;
it=range.begin();
while (run<=l){
while (it!=range.end() && (*it).first<=run) run=max(run,(*it).first+(*it).second),it++;
if (run<=l){
if (it!=range.end()) lim=( (*it).first);
else lim=l+1;
root->update(run,lim-1);
run=lim;
}
}
}
//for (auto i=s.begin();i!=s.end();i++) printf("%d ",*i);
printf("%d\n",root->query(1,l));
}
}
