#ifdef ONPC
#define _GLIBCXX_DEBUG
#endif
#include <bits/stdc++.h>
#include <malloc.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
#pragma GCC optimize("O3")
#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,avx2,fma")
#pragma GCC optimize("unroll-loops")
using namespace __gnu_pbds;
using namespace std;
#define sz(x) (int)x.size()
#define all(x) x.begin(), x.end()
#define rall(x) x.rbegin(), x.rend()
using ll = long long;
using ull = unsigned long long;
using ld = long double;
template<typename T1, typename T2> istream& operator>>(istream& in, pair<T1, T2>& p) {in >> p.first >> p.second; return in;}
template<typename T1, typename T2> ostream& operator<<(ostream& out, pair<T1, T2>& p) {out << p.first << ' ' << p.second; return out;}
template<typename T> istream& operator>>(istream& in, vector<T>& v) {for (auto& x : v) in >> x; return in;}
template<typename T> ostream& operator<<(ostream& out, vector<T>& v) {for (auto& x : v) out << x << ' '; return out;}
template<typename T> ostream& operator<<(ostream& out, set<T>& v) {for (auto& x : v) out << x << ' '; return out;}
template<typename T> ostream& operator<<(ostream& out, multiset<T>& v) {for (auto& x : v) out << x << ' '; return out;}
const int MAX_INT = 2147483647;
const double pi = acos(-1.0);
const int mod = 1e9 + 7;
mt19937_64 rng(chrono::steady_clock::now().time_since_epoch().count());
struct rect {
ll x1, y1, x2, y2;
};
signed main() {
ios_base::sync_with_stdio(false);
cin.tie(nullptr);
vector<rect> a;
ll n, k;
cin >> n >> k;
for (int i = 0; i < k; i++) {
int x1, y1, x2, y2;
cin >> x1 >> y1 >> x2 >> y2;
a.push_back({x1, y1, x2, y2});
}
ll res = n * n;
ll wh_cnt[n + 1], bl_cnt[n + 1];
for (int d = 1; d < n; d++) {
if (n % d) continue;
wh_cnt[0] = 0;
bl_cnt[0] = 0;
for (int i = 1; i <= n; i++) {
int id = (i + d - 1) / d;
wh_cnt[i] = wh_cnt[i - 1];
bl_cnt[i] = bl_cnt[i - 1];
if (id % 2) {
wh_cnt[i]++;
} else {
bl_cnt[i]++;
}
}
ll cur = (n / d) * (n / d) / 2 * d * d;
for (auto [x1, y1, x2, y2] : a) {
cur += (wh_cnt[x2] - wh_cnt[x1 - 1]) * (wh_cnt[y2] - wh_cnt[y1 - 1]) + (bl_cnt[x2] - bl_cnt[x1 - 1]) * (bl_cnt[y2] - bl_cnt[y1 - 1]);
cur -= (wh_cnt[x2] - wh_cnt[x1 - 1]) * (bl_cnt[y2] - bl_cnt[y1 - 1]) + (bl_cnt[x2] - bl_cnt[x1 - 1]) * (wh_cnt[y2] - wh_cnt[y1 - 1]);
}
res = min({res, cur, n * n - cur});
}
cout << res << '\n';
return 0;
}
