#include <bits/stdc++.h>
using namespace std;
using ll = int64_t;
using ull = uint64_t;
using uint = uint32_t;
using ld = long double;
const int MOD = 1e9 + 7;
const int INF = 0x3f3f3f3f;
const ll LINF = 2e18;
const double EPS = 1e-9;
#define EMT ios::sync_with_stdio(0); cin.tie(0);
bool prime_test(int n) {
for(int i = 2; i < n; i++)
if(n % i == 0)
return false;
return true;
}
void solve(int n) {
int k;
cin >> k;
vector<vector<int>> sum(n + 1, vector<int>(n + 1));
for(int i = 0, a, b, c, d; i < k; i++) {
cin >> a >> b >> c >> d;
sum[a][b]++;
}
for(int i = 1; i <= n; i++)
for(int j = 1, g = 0; j <= n; j++)
g += sum[i][j], sum[i][j] = sum[i - 1][j] + g;
//for(int i = 1; i <= n; i++)
//for(int j = 1; j <= n; j++)
//cout << sum[i][j] << " \n"[j == n];
int ans = INF;
for(int i = 1; i < n; i++) {
if(n % i)
continue;
int res = 0, w = n / i;
for(int j = 1; j <= w; j ++) {
for(int k = 1; k <= w; k++) {
if((j + k) & 1) {
res += sum[j * i][k * i] - sum[j * i - i][k * i] - sum[j * i][k * i - i] + sum[j * i - i][k * i - i];
}
else {
res += i * i - (sum[j * i][k * i] - sum[j * i - i][k * i] - sum[j * i][k * i - i] + sum[j * i - i][k * i - i]);
}
}
}
//cout << i << ' ' << res << ' ' << n * n - res << '\n';
ans = min({ans, res, n * n - res});
}
cout << ans << '\n';
}
void solve_2(int n) {
int cnt[2] = {0}, k;
cin >> k;
for(int i = 0, a, b, c, d; i < k; i++) {
cin >> a >> b >> c >> d;
cnt[(a + b) % 2]++;
}
ll a = 1LL * n * n / 2, b = 1LL * n * n - a;
cout << min(cnt[1] + b - cnt[0], cnt[0] + a - cnt[1]) << '\n';
}
signed main() { EMT
int n;
cin >> n;
if(prime_test(n))
solve_2(n);
else
solve(n);
}
/*
6 8
3 3 3 3
1 2 1 2
3 4 3 4
5 5 5 5
4 3 4 3
4 4 4 4
2 1 2 1
3 6 3 6
*/
