#include <bits/stdc++.h>
# define pb push_back
# define ff first
# define ss second
# define nl "\n"
typedef long long ll;
typedef unsigned long long ull;
typedef long double ld;
const ll maxn = 1e5 + 25;
const ll maxl = 22 + 0;
const ll inf = 2e9 + 0;
const ll mod = 998244353;
const ll dx[] = {-1, 1, 0, 0};
const ll dy[] = {0, 0, -1, 1};
using namespace std;
ll n, k;
struct rect
{
ll x1, y1, x2, y2;
} q[maxn];
vector <ll> f(ll x)
{
vector <ll> res;
res.pb(1);
for (ll i = 2; i * i <= x; ++i)
{
if (x % i == 0)
{
res.pb(i);
if (x % (x / i) == 0 && i != x / i) res.pb(x / i);
}
}
return res;
}
void ma1n ()
{
cin >> n >> k;
for (ll i = 1; i <= k; ++i)
{
cin >> q[i].x1 >> q[i].y1 >> q[i].x2 >> q[i].y2;
}
vector <ll> d = f(n);
ll ans = n * n;
for (ll len : d)
{
ll cnt0 = 0, cnt1 = 0;
for (ll i = 1; i <= k; ++i)
{
if (((q[i].x1 + len - 1) / len + (q[i].y1 + len - 1) / len) & 1) cnt1++;
else cnt0++;
}
ll sz = (n * n) / len / len;
ans = min(ans, len * len * (sz / 2) - cnt1 + cnt0);
ans = min(ans, len * len * ((sz + 1) / 2) - cnt0 + cnt1);
}
cout << ans << nl;
}
int main()
{
ios::sync_with_stdio(false);
cin.tie(0); cout.tie(0);
// freopen("mooyomooyo.in", "r", stdin);
// freopen("mooyomooyo.out", "w", stdout);
int ttt = 1;
// cin >> ttt;
for (int test = 1; test <= ttt; ++test)
{
// cout << "Case " << test << ":" << nl;
ma1n();
}
return 0;
}
