#include <bits/stdc++.h>
#define ios ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0)
#define file(s) if (fopen(s".in", "r")) freopen(s".in", "r", stdin), freopen(s".out", "w", stdout)
#define all(a) a.begin() , a.end()
#define F first
#define S second
using namespace std;
using ll = long long;
#define y1 dsfsdf
#define int ll
const int N = 2e5+5 , inf = 2e9 + 7;
const ll INF = 1e18 , mod = 1e9+7 , P = 6547;
int x1[N] , y1[N] , x2[N] , y2[N];
void solve() {
ll n, k;
cin >> n >> k;
if(k == 0) {
ll ans = n*n / 2;
for(int i = 2; i < n; i ++) {
if(n%i == 0) {
int x = i;
if((n/x) % 2) {
ans = min(ans , (n/x) * (n/x) / 2 * x*x);
}
}
}
cout << ans;
return;
}
ll blacks = 0;
for(int i = 1; i <= k; i ++) {
cin >> x1[i] >> y1[i] >> x2[i] >> y2[i];
blacks += (x2[i]-x1[i]+1) * (y2[i]-y1[i]+1);
x1[i] --;
x2[i] --;
y1[i] --;
y2[i] --;
}
ll ans = n*n;
for(int i = 1; i < n; i ++) {
if(n%i == 0) {
int RightBlacks = 0;
for(int j = 1; j <= k; j ++) {
int cnt[2] , cnt1[2];
fill(cnt , cnt+2 , 0);
fill(cnt1 , cnt1+2 , 0);
{
int l = x1[j], r = x2[j];
int l1 = l/i*i+i , r1 = r/i*i-1;
if(l1 <= r1) {
assert((r1-l1+1) % i == 0);
int col = (r1-l1+1) / i;
cnt[0] = col/2 * i;
cnt[1] = col/2 * i;
if(col%2) {
cnt[l1/i % 2] += i;
}
cnt[l/i % 2] += l1-l;
cnt[r/i % 2] += (r-r1);
}
else {
int l1 = l , r1 = r , res;
while(l1 <= r1) {
int md = l1+r1 >> 1;
if(l/i%2 == md/i%2) {
res = md;
l1 = md+1;
}
else {
r1 = md-1;
}
}
cnt[l/i%2] += res-l+1;
cnt[r/i%2] += r-res;
}
}
{
int l = y1[j], r = y2[j];
int l1 = l/i*i+i , r1 = r/i*i-1;
if(l1 <= r1) {
assert((r1-l1+1) % i == 0);
int col = (r1-l1+1) / i;
cnt1[0] = col/2 * i;
cnt1[1] = col/2 * i;
if(col%2) {
cnt1[l1/i % 2] += i;
}
cnt1[l/i % 2] += l1-l;
cnt1[r/i % 2] += (r-r1);
}
else {
int l1 = l , r1 = r , res;
while(l1 <= r1) {
int md = l1+r1 >> 1;
if(l/i%2 == md/i%2) {
res = md;
l1 = md+1;
}
else {
r1 = md-1;
}
}
cnt1[l/i%2] += res-l+1;
cnt1[r/i%2] += r-res;
}
}
RightBlacks += cnt[0] * cnt1[0];
RightBlacks += cnt[1] * cnt1[1];
}
int a = (n/i)*(n/i) / 2 * i*i;
int b = a;
if((n/i) % 2) {
a += i*i;
}
ans = min(ans , a-RightBlacks + (blacks - RightBlacks));
ans = min(ans , b-(blacks - RightBlacks) + RightBlacks);
}
}
cout << ans;
}
/*
*/
main() {
ios;
int tt = 1;
//cin >> tt;
while(tt --) {
solve();
}
return 0;
}
