/*
//\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\\
\\ //
// 271828___182845__904523__53602__ \\
\\ 87___47____13______52____66__24_ //
// 97___75____72______47____09___36 \\
\\ 999595_____74______96____69___67 //
// 62___77____24______07____66__30_ \\
\\ 35___35____47______59____45713__ //
// \\
\\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\//
*/
#include <iostream>
#include <vector>
#include <set>
#include <map>
#include <unordered_map>
#include <unordered_set>
#include <cmath>
#include <climits>
#include <algorithm>
#include <random>
#include <queue>
#include <deque>
#include <iomanip>
#include <string>
#include <tuple>
#include <bitset>
#include <chrono>
#include <ctime>
#include <fstream>
#include <stack>
#include <cstdio>
using namespace std;
using ll = long long;
const int N = 3e5 + 5;
const ll mod = 1e9 + 7, inf = 1e18;
struct rec {
ll x1, y1, x2, y2;
};
bool ev_od(ll x, ll y, ll side) {
ll xx = (x - 1) / side * side + 1, yy = (y - 1) / side * side;
if (xx < x) xx += side;
if (yy < y) yy += side;
if (xx % 2 == yy % 2) return 0;
return 1;
}
void solve() {
ll n, k; cin >> n >> k;
vector<rec> v(k);
for (int i = 0; i < k; ++i) {
cin >> v[i].x1 >> v[i].y1 >> v[i].x2 >> v[i].y2;
}
ll ans = n * n;
for (int i = 1; i < n; ++i) {
if (n % i) continue;
ll od = 0, ev = 0;
for (rec& ii : v) {
ll xx2 = ii.x2 / i * i;
ll xx1 = (ii.x1 - 1) / i * i+ 1;
// 9 / 3
ll yy2 = ii.y2 / i * i;
ll yy1 = (ii.y1 - 1) / i * i + 1;
if (xx1 < ii.x1) xx1 += i;
if (yy1 < ii.y1) yy1 += i;
//if (xx1 != 1) {
// // i = 3,
// // 1 4 7
// // 1 7 13
//}
//++xx1, ++yy1;
//++xx2, ++yy2;
//
// 2 2
// 1 1 2 1
// 2 2 2 2
// 6 2
// 1 1 6 3
// 1 4 6 6
//cout << "! " << i << " ! " << ii.x2 << " " << ii.y2 << " : " << xx1 << " " << yy1 << "\n";
//cout << xx1 << " " << yy1 << " " << xx2 << " " << yy2 << "\n";
//if(i == 2) cout << xx1 << " " << yy1 << " " << xx2 << " " << yy2 << "\n";
if (xx1 <= xx2 && yy1 <= yy2) {
ll ynd = (xx2 - xx1 + 1) / i * (yy2 - yy1 + 1) / i;
ev += (ynd + ((xx1 / i) % 2 == (yy1 / i) % 2)) / 2 * i * i;
od += (ynd + ((xx1 / i) % 2 != (yy1 / i) % 2)) / 2 * i * i;
//if (i == 2) cout << ev << " " << od << "\n";
// bajnel iny uxankyan
// dzax verev
if (ev_od(ii.x1, ii.y1, i)) {
od += (xx1 - ii.x1) * (yy1 - ii.y1);
}
else {
ev += (xx1 - ii.x1) * (yy1 - ii.y1);
}
//if (i == 3) cout << ev << " " << od << "\n";
// aj verev
if (ev_od(xx2, ii.y1, i)) {
od += (yy1 - ii.y1) * (ii.x2 - xx2);
}
else {
ev += (yy1 - ii.y1) * (ii.x2 - xx2);
}
//if (i == 3) cout << ev << " " << od << "\n";
// verev mejtex
ll h = yy1 - ii.y1;
if (ev_od(xx1, ii.y1, i)) {
ll w = xx2 - xx1 + 1, c = w / i;
od += ((c + 1) / 2) * h * i;
ev += c / 2 * h * i;
}
else {
ll w = xx2 - xx1 + 1, c = w / i;
od += c / 2 * h * i;
ev += ((c + 1) / 2) * h * i;
}
//if (i == 3) cout << ev << " " << od << "\n";
// mejtex dzax
ll w = xx1 - ii.x1;
if (ev_od(ii.x1, yy1, i)) {
ll h = yy2 - yy1 + 1, c = h / i;
od += ((c + 1) / 2) * w * i;
ev += c / 2 * w * i;
}
else {
ll h = yy2 - yy1 + 1, c = h / i;
od += c / 2 * w * i;
ev += ((c + 1) / 2) * w * i;
}
//if (i == 3) cout << ev << " " << od << "\n";
// mejtex aj
w = ii.x2 - xx2;
if (ev_od(xx2, yy1, i)) {
ll h = yy2 - yy1 + 1, c = h / i;
od += ((c + 1) / 2) * w * i;
ev += c / 2 * w * i;
}
else {
ll h = yy2 - yy1 + 1, c = h / i;
od += c / 2 * w * i;
ev += ((c + 1) / 2) * w * i;
}
//if (i == 3) cout << ev << " " << od << "\n";
// dzax var
if (ev_od(ii.x1, yy2, i)) {
od += (xx1 - ii.x1) * (ii.y2 - yy2);
}
else {
ev += (xx1 - ii.x1) * (ii.y2 - yy2);
}
//if (i == 3) cout << ev << " " << od << "\n";
// aj var
if (ev_od(xx2, yy2, i)) {
od += (ii.x2 - xx2) * (ii.y2 - yy2);
}
else {
ev += (ii.x2 - xx2) * (ii.y2 - yy2);
}
//if (i == 3) cout << ev << " " << od << "\n";
// var mejtex
h = ii.y2 - yy2;
if (ev_od(xx1, yy2, i)) {
ll w = xx2 - xx1 + 1, c = w / i;
od += ((c + 1) / 2) * h * i;
ev += c / 2 * h * i;
}
else {
ll w = xx2 - xx1 + 1, c = w / i;
od += c / 2 * h * i;
ev += ((c + 1) / 2) * h * i;
}
//if(i == 3) cout << ev << " " << od << "\n";
}
/*
6 3
1 3 1 3
1 4 1 4
2 3 2 3
*/
else if (xx1 >= xx2 && yy1 >= yy2) {
//if(i == 2) cout << "DEBUG\n";
// bajnel petq che, patasxany hashvac e
//cout << "DEBUG\n";
if (ev_od(ii.x1, ii.y1, i)) {
od += (ii.x2 - ii.x1 + 1) * (ii.y2 - ii.y1 + 1);
}
else {
ev += (ii.x2 - ii.x1 + 1) * (ii.y2 - ii.y1 + 1);
}
}
else if (xx1 >= xx2) {
// bajnel ireq uxxankyan, verevi u vari masy arandzin, mejtexy arandzin
// verevi masy
if (ev_od(ii.x1, ii.y1, i)) {
od += (yy1 - ii.y1) * (ii.x2 - ii.x1 + 1);
}
else {
ev += (yy1 - ii.y1) * (ii.x2 - ii.x1 + 1);
}
// vari masy
if (ev_od(ii.x1, yy2, i)) {
od += (ii.y2 - yy2) * (ii.x2 - ii.x1 + 1);
}
else {
ev += (ii.y2 - yy2 + 1) * (ii.x2 - ii.x1 + 1);
}
// mejtexi masy
ll h = yy2 - yy1, c = h / i;
if (ev_od(ii.x1, yy1, i)) {
od += ((c + 1) / 2) * i * (ii.x2 - ii.x1 + 1);
ev += c / 2 * i * (ii.x2 - ii.x1 + 1);
}
else {
od += c / 2 * i * (ii.x2 - ii.x1 + 1);
ev += ((c + 1) / 2) * i * (ii.x2 - ii.x1 + 1);
}
}
else {
// bajnel ireq uxxankyan, dzax u aj masy arandzin, mejtexy arandzin
// dzax masy
if (ev_od(ii.x1, ii.y1, i)) {
od += (ii.x2 - ii.x1 + 1) * (ii.y2 - ii.y1 + 1);
}
else {
ev += (ii.x2 - ii.x1 + 1) * (ii.y2 - ii.y1 + 1);
}
// aj masy
if (ev_od(xx2, ii.y1, i)) {
od += (ii.x2 - xx2) * (ii.y2 - ii.y1 + 1);
}
else {
ev += (ii.x2 - xx2) * (ii.y2 - ii.y1 + 1);
}
// mejtexi masy
ll w = xx2 - xx1, c = w / i;
if (ev_od(xx1, ii.y1, i)) {
od += (c + 1) / 2 * i * (ii.y2 - ii.y1 + 1);
ev += c / 2 * i * (ii.y2 - ii.y1 + 1);
}
else {
od += c / 2 * i * (ii.y2 - ii.y1 + 1);
ev += (c + 1) / 2 * i * (ii.y2 - ii.y1 + 1);
}
}
}
ll edge = n / i, c = (edge * edge + 1) / 2;
ll a = od + c * i * i - ev;
c = edge * edge / 2;
ll b = ev + c * i * i - od;
//cout << min(a, b) << "\n";
ans = min({ ans, a, b });
}
cout << ans << "\n";
}
int main() {
ios_base::sync_with_stdio(0);
cin.tie(NULL);
//int t; cin >> t;
//while (t--)
solve();
}
