#include <bits/stdc++.h>
using namespace std;
#define lli long long int
#define pii pair<int, int>
#define pll pair<lli, lli>
#define X first
#define Y second
#define pb push_back
#define eb emplace_back
#define mp make_pair
#define test(x) cout << #x << ' ' << x << endl
#define printv(x) {\
for (auto a : x) cout << x << ' ';\
cout << endl;\
}
#define all(x) x.begin(), x.end()
#define rall(x) x.rbegin(), x.rend()
const int N = 2000000;
struct range {
int l, r;
bool v;
};
struct Seg {
int l, r, m, tag, sum;
bool lz;
Seg* ch[2];
Seg (int _l, int _r, int k) : l(_l), r(_r), m(l + r >> 1), sum(0), lz(false) {
if (r - l > 1) {
ch[0] = new Seg(l, m, k);
ch[1] = new Seg(m, r, k);
tag = ch[0]->tag + ch[1]->tag;
} else {
tag = (l / k) & 1 ? -1 : 1;
}
}
void pull() {
if (lz) sum = tag;
else if (r - l == 1) sum = 0;
else sum = ch[0]->sum + ch[1]->sum;
}
void modify(int a, int b, bool v) {
if (a <= l && r <= b) lz = v;
else {
if (a < m) ch[0]->modify(a, b, v);
if (m < b) ch[1]->modify(a, b, v);
}
pull();
}
};
int main () {
ios::sync_with_stdio(false);
cin.tie(0);
int n, m;
cin >> n >> m;
vector <int> p;
for (int i = 1; i < n; ++i) if (n % i == 0) p.pb(i);
vector <range> block[n + 1];
for (int i = 0, x1, y1, x2, y2; i < m; ++i) {
cin >> x1 >> y1 >> x2 >> y2, --x1, --y1;
block[x1].pb({y1, y2, true});
block[x2].pb({y1, y2, false});
}
lli ans = 1ll * n * n;
for (int k : p) {
lli cur = 1ll * k * k * (1ll * (n / k) * (n / k) / 2);
Seg root(0, n, k);
for (int i = 0; i <= n; ++i) {
for (range &j : block[i]) {
root.modify(j.l, j.r, j.v);
}
if ((i / k) & 1) {
cur -= root.sum;
} else {
cur += root.sum;
}
}
ans = min({ans, cur, 1ll * n * n - cur});
}
cout << ans << endl;
}
/*
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
*/
