#include <bits/stdc++.h>
using namespace std;
//#pragma GCC optimize ("O3")
//#pragma GCC target ("sse4")
#define endl "\n"
typedef long long ll;
typedef long double ld;
typedef unsigned long long ull;
template<class T, class T2> inline bool chkmax(T &x, const T2 &y) { return x < y ? x = y, 1 : 0; }
template<class T, class T2> inline bool chkmin(T &x, const T2 &y) { return x > y ? x = y, 1 : 0; }
const ll mod = 1e11 + 7;
template<class T> inline void fix(T &x) {if(labs(x) >= mod) {x %= mod;} if(x < 0) {x += mod;}}
#define out(x) cout << __LINE__ << ": " << (#x) << " = " << (x) << endl
const ll MAX_N = 1e5 + 110;
ll xl[MAX_N], yl[MAX_N], xr[MAX_N], yr[MAX_N];
ll n, k;
ll sz;
ll howm(ll w, ll l, ll r) {
if(l / sz == r / sz) {
if(l / sz % 2ll == w) {
return r - l + 1ll;
} else {
return 0;
}
}
ll ret = 0;
{
ll nxt = (l + sz) / sz * sz;
if(l / sz % 2ll == w) {
ret += nxt - l;
}
l = nxt;
}
{
ll nxt = r / sz * sz - 1ll;
if(r / sz % 2ll == w) {
ret += r - nxt;
}
r = nxt;
}
ret += (r / sz - l / sz) / 2ll * sz;
if(l / sz % 2ll == r / sz % 2ll && l / sz % 2ll == w) {
ret += sz;
}
return ret;
}
ll eval(ll x) {
sz = x;
ll badw = 0, goodb = 0;
ll cnt = (n * n) / (x * x);
goodb = cnt / 2ll * sz * sz;
for(ll i = 0; i < k; i ++) {
ll r0 = howm(0, xl[i], xr[i]);
ll r1 = howm(1, xl[i], xr[i]);
ll c0 = howm(0, yl[i], yr[i]);
ll c1 = howm(1, yl[i], yr[i]);
badw += r0 * c0 + r1 * c1;
goodb -= r0 * c1 + r1 * c0;
}
return min(badw + goodb, n * n - badw - goodb);
}
signed main() {
ios_base::sync_with_stdio(false); cin.tie(NULL); cout.tie(NULL);
cin >> n >> k;
ll ans = mod;
for(ll i = 0; i < k; i ++) {
cin >> xl[i] >> yl[i] >> xr[i] >> yr[i];
xl[i] --;
yl[i] --;
xr[i] --;
yr[i] --;
}
for(ll x = 1; x < n; x ++) {
if(n % x != 0) {continue;}
chkmin(ans, eval(x));
}
cout << ans << endl;
return 0;
}
/*
6 8
3 3 3 3
1 2 1 2
3 4 3 4
5 5 5 5
4 3 4 3
4 4 4 4
2 1 2 1
3 6 3 6
*/
