#include <bits/allocator.h>
#pragma GCC optimize("O3,unroll-loops")
#pragma GCC target("avx,avx2")
#include <bits/stdc++.h>
using namespace std;
#define taskname "default"
bool mode;
// mode = 0: (1, 1) = black
// mode = 1: (1, 1) = white
int n; long long sz;
array<int, 4> rect[100008];
int pfr[100008], pfc[100008];
void build(int m) {
for (int i = 1; i <= n; ++i) {
pfr[i] = pfr[i - 1] + ((((i - 1) / sz) & 1) ^ m ? -1 : +1);
pfc[i] = pfc[i - 1] + ((((i - 1) / sz) & 1) ? -1 : +1);
}
}
long long query(int x1, int y1, int x2, int y2) {
return (1LL * (x2 - x1 + 1) * (y2 - y1 + 1) + 1LL * (pfr[x2] - pfr[x1 - 1]) * (pfc[y2] - pfc[y1 - 1])) / 2;
}
signed main() {
ios_base::sync_with_stdio(0);
cin.tie(0); cout.tie(0);
int m; cin >> n >> m;
long long tot = 0, expected, same, edit_dist, ans = 1LL * n * n;
for (int i = 1; i <= m; ++i) {
cin >> rect[i][0] >> rect[i][1] >> rect[i][2] >> rect[i][3];
tot += 1LL * (rect[i][2] - rect[i][0] + 1) * (rect[i][3] - rect[i][1] + 1);
}
vector<int> divs;
for (int d = 1; d < n; ++d) if (n % d == 0) {
divs.push_back(d);
}
for (int d : divs) {
sz = d;
mode = 0; same = 0; build(mode);
expected = sz * sz * ((1LL * (n / sz) * (n / sz) + 1 - mode) / 2);
for (int i = 1; i <= m; ++i)
same += query(rect[i][0], rect[i][1], rect[i][2], rect[i][3]);
edit_dist = tot - same + expected - same;
ans = min(ans, edit_dist);
same = 0; mode = 1; build(mode);
expected = sz * sz * ((1LL * (n / sz) * (n / sz) + 1 - mode) / 2);
for (int i = 1; i <= m; ++i)
same += query(rect[i][0], rect[i][1], rect[i][2], rect[i][3]);
edit_dist = tot - same + expected - same;
ans = min(ans, edit_dist);
}
cout << ans;
}
