#include <bits/stdc++.h>
using namespace std;
const int N = 100005;
struct Rec {
int x1, y1, x2, y2;
} rec[N];
int n, m;
long long res = 1e18;
void cal(int x, int l, int r, int *cnt) {
cnt[0] = cnt[1] = 0;
if (l / x != r / x) {
cnt[0] += ( (r / x - 1) / 2 - l / x / 2 ) * x;
if (r / x % 2 == 0) cnt[0] += r - r / x * x + 1;
if (l / x % 2 == 0) cnt[0] += (l / x + 1) * x - l;
}
else {
if (l / x % 2 == 0) cnt[0] += r - l + 1;
}
cnt[1] = r - l + 1 - cnt[0];
// cout << "# " << cnt[0] << ' ' << cnt[1] << '\n';
}
void solve(int fix) {
long long val1 = 0, val2 = 0;
// change all white -> black
val1 = 1LL * (n / fix) * (n / fix) / 2 * fix * fix;
val2 = 1LL * n * n - val1;
// cout << "#val " << val1 << ' ' << val2 << '\n';
for (int i = 1; i <= m; ++i) {
int cntx[2], cnty[2];
// cout << "#X\n";
cal(fix, rec[i].x1, rec[i].x2, cntx);
// cout << "#Y\n";
cal(fix, rec[i].y1, rec[i].y2, cnty);
val1 += 1LL * cntx[0] * cnty[0] + 1LL * cntx[1] * cnty[1]; // black -> white
val1 -= 1LL * cntx[0] * cnty[1] + 1LL * cntx[1] * cnty[0]; // black -> black
val2 += 1LL * cntx[0] * cnty[1] + 1LL * cntx[1] * cnty[0]; // black -> white
val2 -= 1LL * cntx[0] * cnty[0] + 1LL * cntx[1] * cnty[1]; // black -> black
}
// cout << "#at " << fix << ' ' << val1 << ' ' << val2 << '\n';
res = min(res, min(val1, val2));
}
int main() {
ios::sync_with_stdio(false);
cin >> n >> m;
for (int i = 1; i <= m; ++i) {
cin >> rec[i].x1 >> rec[i].y1 >> rec[i].x2 >> rec[i].y2;
rec[i].x1--, rec[i].x2--, rec[i].y1--, rec[i].y2--;
}
// solve(2);
for (int i = 1; i < n; ++i) {
if (n % i == 0) solve(i);
}
cout << res;
}
