#include <bits/stdc++.h>
using namespace std;
#define pb push_back
#define mp make_pair
#define f first
#define s second
#define ll long long
#define ld long double
#define all(_v) _v.begin(), _v.end()
#define sz(_v) (int)_v.size()
#define pii pair <int, int>
#define pll pair <ll, ll>
#define veci vector <int>
#define vecll vector <ll>
const int dx[4] = {1, -1, 0, 0};
const int dy[4] = {0, 0, -1, 1};
const double PI = 3.1415926535897932384626433832795;
const double eps = 1e-9;
const int MOD1 = 1e9 + 7;
const int MOD2 = 998244353;
const int MAXN = 2e5 + 10;
ll n;
ll cnt[MAXN];
ll get(ll r, ll k) {
ll nr = r - r % k;
ll bl = nr / k;
ll cnt = (bl + 1) / 2 * k;
if(bl % 2 == 0) cnt += r - nr;
return cnt;
}
void solve() {
int k;
cin >> n >> k;
vecll dv;
dv.pb(1);
for(ll i = 2; i * i <= n; ++i) {
if(n % i == 0) {
dv.pb(i);
if(i * i != n) dv.pb(n / i);
}
}
sort(all(dv));
for(auto i : dv) {
ll cnt1 = get(n, i);
cnt[i] = cnt1 * i * (((n / i) + 1) / 2) + (n - cnt1) * i * (n / i - (((n / i) + 1) / 2));
}
for(int rect = 1; rect <= k; ++rect) {
ll x1, y1, x2, y2;
cin >> x1 >> y1 >> x2 >> y2;
for(auto i : dv) {
ll row_cnt[2];
row_cnt[1] = get(x2, i) - get(x1 - 1, i);
row_cnt[0] = x2 - x1 + 1 - row_cnt[1];
ll col_cnt[2];
col_cnt[1] = get(y2, i) - get(y1 - 1, i);
col_cnt[0] = y2 - y1 + 1 - col_cnt[1];
cnt[i] -= row_cnt[1] * col_cnt[1];
cnt[i] -= row_cnt[0] * col_cnt[0];
cnt[i] += row_cnt[0] * col_cnt[1];
cnt[i] += row_cnt[1] * col_cnt[0];
}
}
ll ans = 4e18;
for(auto i : dv) ans = min(ans, min(cnt[i], n * n - cnt[i]));
cout << ans;
}
int main() {
ios_base::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
int CNT_TESTS = 1;
///cin >> CNT_TESTS;
for(int NUMCASE = 1; NUMCASE <= CNT_TESTS; ++NUMCASE) {
solve();
if(NUMCASE != CNT_TESTS) cout << '\n';
}
return 0;
}
