#include <bits/stdc++.h>
using namespace std;
int n,k,i,x,y,x2,y2;
struct dreptunghi{
int x,y,x2,y2;
};
vector <dreptunghi> v;
long long count_(int x, int y, int val){
if (!x || !y)
return 0;
long long sol = 1LL * (x/val) * (y/val) / 2 * val * val;
int lastx = (x/val) * val, lasty = (y/val) * val;
if (x/val % 2)
sol += (y/val + 1)/2 * val * (x - lastx);
else sol += (y/val/2) * val * (x - lastx);
if (y/val % 2)
sol += (x/val + 1)/2 * val * (y - lasty);
else sol += (x/val/2) * val * (y - lasty);
if (!(x/val % 2 == y/val%2))
sol += (x - lastx) * (y - lasty);
return sol;
}
long long solve (int val){
long long albe = 1LL * (n/val) * (n/val) / 2 * val * val; /// cate ar trebui sa fac albe daca e toata tabla neagra
long long negre = 1LL * n * n - albe;
for (auto it : v){
int x = it.x, y = it.y, x2 = it.x2, y2 = it.y2;
long long cnt = count_(x2,y2,val) - count_(x2,y-1,val) - count_(x-1,y2,val) + count_(x-1,y-1,val);
negre -= (x2-x+1) * (y2-y+1) - cnt; /// nu are sens sa le fac pe astea negre
negre += cnt; /// trb sa le fac la loc albe pe astea
albe += (x2-x+1) * (y2-y+1) - cnt;
albe -= cnt;
}
return min (albe,negre);
}
int main (){
//ifstream cin ("date.in");
//ofstream cout ("date.out");
cin>>n>>k;
for (i=1;i<=k;i++){
cin>>x>>y>>x2>>y2;
v.push_back({x,y,x2,y2});
}
long long sol = 1LL * n * n;
for (int d=1;d<n;d++){
if (n % d == 0)
sol = min (sol,solve(d));
}
cout<<sol;
return 0;
}
