#include <bits/stdc++.h>
using namespace std;
#define F first
#define S second
#define int long long
struct rect{
int x1, y1, x2, y2;
};
int d;
int get(int x, int y){
if(x<=0 || y<=0)return 0;
int x1=x/d;
int y1=y/d;
int ret=0;
if(x1!=0 && y1!=0){
if(x1&y1&1)ret+=d*d;
}
int rx=x-x1*d;
int ry=y-y1*d;
if(rx==0 && ry==0)return ret;
if(y1&1){
if(x1&1)ret-=d*rx;
else ret+=d*rx;
}
if(x1&1){
if(y1&1)ret-=d*ry;
else ret+=d*ry;
}
if((x1+y1)&1)ret-=rx*ry;
else ret+=rx*ry;
return ret;
}
signed main()
{
ios_base::sync_with_stdio(0);
cin.tie(0);
int n, k;
cin >> n >> k;
rect a[k];
cout << "\n\n";
for(int i=0; i< k; i++){
cin >> a[i].x1 >> a[i].y1 >> a[i].x2 >> a[i].y2;
}
int ans=1e12;
for(d=1; d<n; d++){
if(n%d!=0)continue;
int flip=d*d*(((n*n)/(d*d)+1)/2);
for(int i=0; i<k; i++){
flip-=get(a[i].x2, a[i].y2)+get(a[i].x1-1, a[i].y1-1)-get(a[i].x1-1, a[i].y2)-get(a[i].x2, a[i].y1-1);
}
ans=min({ans, flip, n*n-flip});
}
cout << ans << '\n';
}
