#include <bits/stdc++.h>
using namespace std;
using ll = long long;
#define vi vector<long long>
#define all(x) x.begin(), x.end()
#define endl "\n"
#define pr pair<ll, ll>
#define ff first
#define ss second
void solution();
int main(){
ios::sync_with_stdio(false);
cin.tie(nullptr);
solution();
return 0;
}
void solution() {
ll L, R; cin >> L >> R;
vector<vi> walls(R);
for (int i = 0; i < R; i++) {
ll x; cin >> x;
walls[i].resize(x);
for (ll &z : walls[i]) cin >> z;
}
vector<pr> cant;
for (int i = 0; i < R; i++) {
ll sum = accumulate(all(walls[i]), 0ll);
ll dif = L-sum+1;
for (int j = walls[i].size()-1; j >= 0; j--) {
ll r = sum;
sum -= walls[i][j];
ll l = sum + dif;
if (l <= r) cant.push_back({l, r});
}
}
if (cant.size() == 0) {
cout << 0 << endl;
return;
}
sort(all(cant));
vector<pr> nw;
ll l = cant[0].ff, r = cant[0].ss;
for (auto [x, y] : cant) {
if (x <= r) r = max(r, y);
else {
nw.push_back({l, r});
l = x; r = y;
}
}
nw.push_back({l, r});
ll ans = 0;
for (auto [x, y] : nw) {
ans += y-x+1;
}
cout << ans << endl;
}
