#include<bits/stdc++.h>
using namespace std;
#define pb push_back
#define ll long long
#define ff first
#define ss second
#define PI 3.14159265359
ll n,m,t,p,h,a,b,c,d,e,f,i,j,k,r,l,mod=1000000007,mod1=998244353,MAX=1e18,ans;
ll X1[100001],X2[100001],Y1[100001],Y2[100001];
string s,u;
ll df[101];
vector<pair<ll,ll> >v;
vector<ll>dv[101];
void dfs(ll x){
df[x]=1;
for(ll i=0;i<dv[x].size();i++){
if(df[dv[x][i]]==0){
dfs(dv[x][i]);
}
}
}
ll fastPow(ll a,ll b){
ll d=1;
while(b>0){
if(b%2==1){
d=d*a%mod;
}
b/=2;
a=a*a%mod;
}
return d;
}
ll check(){
ll c=n/i;
ll b,w;
if(c%2==0){
b=n*n/2;
w=b;
}
else{
b=(n-i)*(n+i)/2;
w=b+(i*i);
}
ll num[2]={0};
for(ll j=1;j<=k;j++){
num[(((X1[j]-1)/i)+((Y1[j]-1)/i))%2]++;
}
return min((w-num[0])+num[1],(b-num[1])+num[0]);
}
int main(){
cin>>n>>k;
for(i=1;i<=k;i++){
cin>>X1[i]>>Y1[i]>>X2[i]>>Y2[i];
}
ans=n*n;
for(i=1;i<n;i++){
if(n%i==0){
ans=min(ans,check());
}
}
cout<<ans;
}
