#include<bits/stdc++.h>
using namespace std;
#define jizz ios_base::sync_with_stdio(false);cin.tie(NULL);
typedef long long ll;
typedef pair<int,int> pii;
#define F first
#define S second
#define FOR(i,n) for(int i=0;i<n;i++)
#define FOO(i,a,b) for(int i=a;i<=b;i++)
#define OOF(i,a,b) for(int i=a;i>=b;i--)
#define ALL(x) (x).begin(),(x).end()
#define pb push_back
#define mkp make_pair
const int MAXN=1E5+10;
ll n, k;
pii point[MAXN];
ll solve(ll i){
ll col=i*i*(((n/i)*(n/i)+1)/2), rights=0, wrongs=0;
for(int j=0;j<k;j++){
if((point[j].F/i)%2==(point[j].S/i)%2){
rights++;
} else{
wrongs++;
}
}
return min(col-rights+wrongs,(n*n-col)-wrongs+rights);
}
int main(){ jizz
cin>>n>>k;
FOR(i,k){
int x1, y1, x2, y2;
cin>>x1>>y1>>x2>>y2;
point[i]=mkp(x1-1,y1-1);
}
ll ans=n*n;
for(ll i=1;i*i<=n;i++){
if(n%i==0){
ans=min(ans,solve(i));
if(n/i<n) ans=min(ans,solve(n/i));
}
}
cout<<ans<<"\n";
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
*/
