#include <iostream>
#include <vector>
#include <deque>
using namespace std;
using vi = vector<int>;
using vvi = vector<vi>;
using pii = pair<int, int>;
#define sz(x) (int(x.size()))
int main()
{
int L, R;
cin >> L >> R;
vi S(1+R, 0);
vvi blocks(1+R);
vi delta(1+L+1, 0);
for(int r = 1; r <= R; r++)
{
// cerr << "\n\n\n";
// cerr << "layer = " << r << '\n';
int X;
cin >> X;
for(int x = 1; x <= X; x++)
{
int Z;
cin >> Z;
blocks[r].push_back(Z);
S[r] += Z;
}
int left_sum = 0;
deque<pii> H;
for(int x = 0; x <= X; x++)
{
// cerr << left_sum << " , " << S[r] - left_sum << " : " << left_sum + 1 << ' ' << L - (S[r] - left_sum) << '\n';
H.push_back({left_sum + 1, L - (S[r] - left_sum)});
if(x != X)
{
left_sum += blocks[r][x];
}
}
while(!H.empty())
{
while(sz(H) >= 2 && H[sz(H) - 2].second >= H[sz(H) - 1].first)
{
H[sz(H) - 2].second = H[sz(H) - 1].second;
H.pop_back();
}
pii h = H.back();
delta[h.first]++;
delta[h.second + 1]--;
H.pop_back();
}
}
int ans = 0;
int curr = 0;
for(int i = 1; i <= L; i++)
{
// cerr << delta[i] << ' ';
curr += delta[i];
ans += (curr < R);
// cerr << i << " : " << curr << '\n';
}
// cerr << '\n';
cout << ans << '\n';
}
