/*#pragma GCC optimize("O3")
#pragma GCC optimization("Ofast,unroll-loops")
#pragma GCC target("avx2,bmi,bmi2,lzcnt,popcnt")*/
#include <bits/stdc++.h>
//#include "algotester_generator.h"
/*#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>*/
#define ll long long
#define ll1 long long
#define ull unsigned long long
#define dou long double
#define str string
#define vll vector<ll>
#define vi vector<int>
#define pll pair<ll, ll>
#define vpll vector<pll>
#define vbool vector<bool>
#define vstr vector<str>
#define vvll vector<vll>
#define pb push_back
#define pf push_front
#define endl "\n"
#define fr first
#define se second
// #define sortcmp(a) sort(a.begin(), a.end(), cmp)
#define sort(a) sort(a.begin(), a.end())
#define reverse(a) reverse(a.begin(), a.end())
#define speed ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0)
#define INF 1000000000000000000
#define ordered_set tree<ll, null_type, less_equal<ll>, rb_tree_tag, tree_order_statistics_node_update>
using namespace std;
//using namespace __gnu_pbds;
mt19937 rng(time(0));
ll randll(ll l, ll r){
return uniform_int_distribution<ll>(l, r)(rng);
}
int main(){
speed;
ll n, m;
cin >> n >> m;
ll maxl = 0;
vpll v;
for(int i = 0; i < m; i ++){
ll k, s = 0;
cin >> k;
vll a(k);
for(int j = 0; j < k; j ++){
cin >> a[j];
s += a[j];
}
ll p = 0;
for(int j = 0; j < k; j ++){
s -= a[j];
ll k1 = n-p-s-a[j];
//cout << p << ' ' << s << ' ' << k1 << ' ' << a[j] << endl;
if(k1*2 < n-p-s) v.pb({p+k1, n-s-k1});
p += a[j];
}
cout << endl;
}
sort(v);
ll res = 0;
/*for(auto i : v){
cout << i.fr << ' ' << i.se << endl;
}*/
if(v.empty()){
cout << 0 << endl;
return 0;
}
ll l = v[0].fr, r = v[0].se;
for(int i = 1; i < v.size(); i ++){
if(v[i].fr <= r){
r = max(r, v[i].se);
}
else{
res += r-l;
l = v[i].fr, r = v[i].se;
}
}
res += r-l;
cout << res << endl;
}
