//Just try and the idea will come!
#include<bits/stdc++.h>
#define int long long int
#define fr first
#define sc second
using namespace std;
int n,k,i,j,x,y,res;
pair<int,int>p[100001],s[100001];
int get(int x1,int y1,int x2,int y2){
if(x1>x2||y1>y2)return 0;
int res=(x2-x1+1)*((y2-y1+1)/2);
if((y2-y1+1)&1){
res+=(x2-x1+1)/2;
if((x1+y1)%2==0&&(x2-x1+1)%2==1)res++;
}
return res;
}
int get_x(int x1,int y1,int x2,int y2,int f){
if(x1>x2||y1>y2)return 0;
int res,x,xx;
x=(x1+f-1)/f;
xx=(x2-f+1)/f;
res=get(x,y1/f,xx,y1/f)*(y2-y1+1);
if((x1+y1)%2==0)res+=max(0ll,(x*f-1-x1+1))*(y2-y1+1);
if((x2+y2)%2==0)res+=max(0ll,(x2-xx*f))*(y2-y1+1);
return res;
}
int get_y(int x1,int y1,int x2,int y2,int f){
if(x1>x2||y1>y2)return 0;
int res,x,yy;
y=(y1+f-1)/f;
yy=(y2-f+1)/f;
res=get(x/f,y,x/f,yy)*(x2-x1+1);
if((x1+y1)%2==0)res+=max(0ll,(y*f-1-y1+1))*(x2-x1+1);
if((x2+y2)%2==0)res+=max(0ll,(y2-yy*f))*(x2-x1+1);
return res;
}
int count_white(int x1,int y1,int x2,int y2,int f){
int x,y,xx,yy,res;
x=(x1+f-1)/f;
y=(y1+f-1)/f;
xx=(x2-f+1)/f;
yy=(y2-f+1)/f;
res=f*f*get(x,y,xx,yy);
res+=get_x(x1,y1,x2,y-1,f)+get_x(x1,yy+1,x2,y2,f);
res+=get_y(x1,y,x-1,yy,f)+get_y(xx+1,y,x2,yy,f);
return res;
}
int get(int f){
int cnt=0,c[2],x;
c[0]=c[1]=0;
for(int i=0;i<k;i++){
x=get(s[i].fr/f,s[i].sc/f,p[i].fr/f,p[i].sc/f);
c[0]+=x;
c[1]+=(p[i].fr-s[i].fr+1)*(p[i].sc-s[i].sc+1)-x;
}
int m=n/f;
int res=f*f*((m/2)*m+((m%2)*(m/2)))-c[1]+c[0];
res=min(res,f*f*((m/2)*m+((m%2)*((m+1)/2)))-c[0]+c[1]);
return res;
}
main(){
scanf("%lld%lld",&n,&k);
for(i=0;i<k;i++){
scanf("%lld%lld%lld%lld",&s[i].fr,&s[i].sc,&p[i].fr,&p[i].sc);
p[i].fr--;
p[i].sc--;
s[i].fr--;
s[i].sc--;
}
res=get(1);
for(j=2;j*j<=n;j++){
if(n%j==0){
res=min(res,get(j));
res=min(res,get(n/j));
}
}
printf("%lld",res);
}
