#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
const int N=100005;
int l1[N],l2[N],r1[N],r2[N];
ll prsp[N],prsv[N];
int main(){
ll n;
int k;
cin>>n>>k;
for (int i=0;i<k;i++){
cin>>l1[i]>>l2[i]>>r1[i]>>r2[i];
}
ll mn=LLONG_MAX;
for (ll i=1;i<n;i++){
if (n%i)continue;
ll qan;
if ((n/i)%2) qan=(n*n-i*i)/2ll;
else qan=(n*n)/2;
prsp[0]=prsv[0]=0;
//cout<<i<<" "<<qan<<endl;
for (ll j=1;j<=n;j++){
prsp[j]=prsp[j-1];
prsv[j]=prsv[j-1];
if (((j-1ll)/i)%2){
prsv[j]++;
}
else{
prsp[j]++;
}
//cout<<prsv[j]<<" "<<prsp[j]<<endl;
}
for (int j=0;j<k;j++){
ll vqansp,vqansv,kqansp,kqansv;
vqansp=prsp[r1[j]]-prsp[l1[j]-1];
vqansv=prsv[r1[j]]-prsv[l1[j]-1];
kqansp=prsp[r2[j]]-prsp[l2[j]-1];
kqansv=prsv[r2[j]]-prsv[l2[j]-1];
//cout<<vqansp<<" "<<vqansv<<" "<<kqansp<<" "<<kqansv<<endl;
qan+=(vqansp*kqansp+vqansv*kqansv)-(vqansp*kqansv+vqansv*kqansp);
}
//cout<<qan<<endl;
mn=min(mn,min(qan,n*n-qan));
}
cout<<mn<<endl;
return 0;
}
