// #pragma GCC optimize("Ofast")
// #pragma GCC targt("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,avx2,fma")
// #pragma GCC optimize("unroll-loops")
#include "bits/stdc++.h"
// #include <ext/pb_ds/assoc_container.hpp>
// #include <ext/pb_ds/trie_policy.hpp>
// #include <ext/rope>
using namespace std;
// using namespace __gnu_pbds;
// using namespace __gnu_cxx;
#define li long long
#define ld long double
#define ii pair<int, int>
#define vi vector<int>
#define vvi vector<vi>
#define fi first
#define se second
#define mp make_pair
#define pb push_back
#define pf push_front
#define eb emplace_back
#define em emplace
#define ob pop_back
#define om pop
#define of pop_front
#define fr front
#define bc back
#define fori(i, a, b) for(int i = (int) (a); i <= (int) (b); ++i)
#define ford(i, a, b) for(int i = (int) (a); i >= (int) (b); --i)
#define all(x) begin(x), end(x)
#define sz(x) ((int)(x).size())
#define bitc __builtin_popcountll
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
#define rand rng
#define endl '\n'
#define sp ' '
#define fastio() ios_base::sync_with_stdio(false); cin.tie(NULL); cout.tie(NULL);
void solve();
signed main() {
// freopen("output.out","w",stdout);
fastio();
int tc = 1;
// cin >> tc;
fori(test, 1, tc) {
solve();
}
return 0;
}
const ld pi = 4 * atan(1.0), eps = 1e-9;
#define int long long
const int maxn = 200000 + 5, mod = 924844033;
const int inf = LLONG_MAX / 2;
int n, m;
int sum = 0;
vector<pair<ii, ii> > al;
int get(int i, int k) {
// cout << i << sp << min(i % (2 * k), k)<< sp << (i / (2 * k) * k) << endl;
return min(i % (2 * k), k) + (i / (2 * k) * k);
}
void solve() {
cin >> n>> m;
fori(i,1 , m) {
int a, b, c, d;
cin >> a >> b >> c >> d;
al.eb(ii(a, b), ii(c, d));
}
int ans= inf;
fori(i, 1, n - 1) {
if(n % i == 0) {
int blocks = n * n / (i * i); int black = (blocks + 1) / 2 * i * i;
// cout << blocks << endl;
int a1 = black, a2 = n * n - black;
// cout<< "a: " << a1 << sp << a2 << endl;
for(auto t : al) {
int a = t.fi.fi, b = t.fi.se, c = t.se.fi, d = t.se.se;
int area = (c - a + 1) * (d- b + 1);
int h = get(c, i) - get(a - 1, i), w = get(d, i) - get(b- 1, i);
int smblack = h * w + (c - a + 1 - h) * (d - b + 1 - w);
// cout << i << sp << h << sp << w << sp << smblack << endl;;
a1 -= smblack;
a2 -= area - smblack;
a1 += area - smblack;
a2 += smblack;
// cout << a1 << sp << a2 << ":::" << endl;
}
ans = min(ans, a1);
ans = min(ans, a2);
}
}
cout << ans;
}
