#include <bits/stdc++.h>
#define all(i) i.begin(), i.end()
#define rall(i) i.rbegin(), i.rend()
using namespace std;
typedef long long ll;
typedef pair<int, int> pi;
struct sq {
int u, l, d, r;
sq() = default;
sq(int _u, int _l, int _d, int _r) : u(_u), l(_l), d(_d), r(_r) {}
};
int main() {
ios::sync_with_stdio(0), cin.tie(0);
int n, k;
cin >> n >> k;
sq a[k];
for (sq &i : a) cin >> i.u >> i.l >> i.d >> i.r;
auto calc = [](int d, int r, int len) {
ll tmp[4];
tmp[0] = 1ll * (d / len) * (r / len) / 2 * len * len;
tmp[1] = 1ll * (r % len) * ((d / len + (r % (2 * len) < len ? 0 : 1)) / 2) * len;
tmp[2] = 1ll * (d % len) * ((r / len + (d % (2 * len) < len ? 0 : 1)) / 2) * len;
tmp[3] = ((d % (2 * len) < len) ^ (r % (2 * len) < len) ? 1ll * (d % len) * (r % len) : 0);
return tmp[0] + tmp[1] + tmp[2] + tmp[3];
};
/*
* 0101
* 1010
* 0101
* 1010
*/
ll ans = 1ll * n * n;
for (int i = 1; i < n; ++i) if (n % i == 0) {
ll cnt[4]{};
for (int j = 0; j < k; ++j) {
ll tmp = calc(a[j].d, a[j].r, i) - calc(a[j].d, a[j].l - 1, i) - calc(a[j].u - 1, a[j].r, i) + calc(a[j].u - 1, a[j].l - 1, i);
cnt[3] += tmp;
cnt[1] += 1ll * (a[j].d - a[j].u + 1) * (a[j].r - a[j].l + 1) - tmp;
}
cnt[2] = calc(n, n, i) - cnt[3];
cnt[0] = 1ll * n * n - cnt[1] - cnt[2] - cnt[3];
ans = min(ans, cnt[1] + cnt[2]);
ans = min(ans, cnt[0] + cnt[3]);
}
cout << ans;
}
