#include <bits/stdc++.h>
#define int long long
using namespace std;
#define file ""
#define mp make_pair
#define fi first
#define se second
#define all(x) x.begin(), x.end()
#define getbit(x, i) (((x) >> (i)) & 1)
#define bit(x) (1LL << (x))
#define popcount __builtin_popcountll
mt19937_64 rd(chrono::steady_clock::now().time_since_epoch().count());
int rand(int l, int r) {
return l + rd() % (r - l + 1);
}
const int N = 1e6 + 5;
const int mod = (int)1e9 + 7; // 998244353;
const int lg = 25; // lg + 1
const int oo = 1e9;
const long long ooo = 1e18;
template<class X, class Y> bool mini(X &a, Y b) {
return a > b ? (a = b, true) : false;
}
template<class X, class Y> bool maxi(X &a, Y b) {
return a < b ? (a = b, true) : false;
}
void add(int &a, int b) {
a += b;
if (a >= mod) a -= mod;
if (a < 0) a += mod;
}
struct rec {
int x, y, u, v;
rec (int _x = 0, int _y = 0, int _u = 0, int _v = 0) {
x = _x;
y = _y;
u = _u;
v = _v;
}
};
int n, k;
vector<rec> subrec;
int area = 0;
int res = ooo;
signed main() {
ios::sync_with_stdio(false);
cin.tie(0);
// freopen(file".inp", "r", stdin);
// freopen(file".out", "w", stdout);
cin >> n >> k;
for (int i = 1; i <= k; ++i) {
int x, y, u, v;
cin >> x >> y >> u >> v;
--x, --y, --u, --v;
subrec.push_back(rec(x, y, u, v));
area += (u - x + 1) * (v - y + 1);
}
for (int i = 1; i < n; ++i) if (n % i == 0) {
int d = n / i;
int a = (d * d + 1) / 2 * i * i;
int b = (d * d) / 2 * i * i;
int cnt = 0;
for (auto [x, y, u, v] : subrec) {
if ((x / i) % 2 == (y / i) % 2) ++cnt;
}
res = min(res, (a - cnt) + (area - cnt));
res = min(res, (b - (area - cnt)) + cnt);
}
cout << res;
return 0;
}
/*
*/
