#include<bits/stdc++.h>
using namespace std;
#define rep(i,a,b) for(int i = a; i<int(b);++i)
#define all(v) v.begin(),v.end()
#define sz(v) v.size()
#define trav(a,c) for(auto a: c)
typedef long long ll;
typedef vector<ll> vi;
typedef pair<ll,ll> pii;
ll n,k;
ll ceilDiv(ll a,ll b){
return a/b + (a%b!=0);
}
ll getNumBlack(ll x1,ll y1,ll x2,ll y2, ll sq){
ll x12 = ceilDiv(x1,sq);
ll y12 = ceilDiv(y1,sq);
ll x22 = x2/sq;
ll y22 = y2/sq;
if((x12+y12)%2==0){ //black in left lower corner
ll r1,r2;
if(x22<x12){
r1 = 0;
r2 = x2-x1;
} else if((x22-x12+2)%2==1){
r1 = ((x22-x12)/2+1)*sq;
r2 = ((x22-x12)/2)*sq + (x2-x22*sq) + (x12*sq-x1);
} else {
r1 = (x22-x12)/2*sq + (x2-x22*sq);
r2 = (x22-x12)/2*sq + (x12*sq-x1);
}
ll c1,c2;
if(y22<y12){
c1 = 0;
c2 = y2-y1;
} else if((y22-y12+2)%2==1){
c1 = ((y22-y12)/2+1)*sq;
c2 = ((y22-y12)/2)*sq + (y2-y22*sq) + (y12*sq-y1);
} else {
c1 = (y22-y12)/2*sq + (y2-y22*sq);
c2 = (y22-y12)/2*sq + (y12*sq-y1);
}
return r1*c1+r2*c2;
} else {
ll r1,r2;
if(x22<x12){
r1 = 0;
r2 = x2-x1;
} else if((x22-x12+2)%2==1){
r1 = ((x22-x12)/2+1)*sq;
r2 = ((x22-x12)/2)*sq + (x2-x22*sq) + (x12*sq-x1);
} else {
r1 = (x22-x12)/2*sq + (x2-x22*sq);
r2 = (x22-x12)/2*sq + (x12*sq-x1);
}
ll c1,c2;
if(y22<y12){
c1 = 0;
c2 = y2-y1;
} else if((y22-y12)%2==1){
c1 = ((y22-y12)/2+1)*sq;
c2 = ((y22-y12)/2)*sq + (y2-y22*sq) + (y12*sq-y1);
} else {
c1 = (y22-y12)/2*sq + (y2-y22*sq);
c2 = (y22-y12)/2*sq + (y12*sq-y1);
}
return r1*c2+r2*c1;
}
}
vector<tuple<ll,ll,ll,ll> > v;
ll getCost(ll sq, bool startWhite){
ll blackToBlack = 0;
ll blackToWhite = 0;
ll whiteToWhite, whiteToBlack;
if((n/sq)%2==1){
whiteToWhite = ((n/sq)*(n/sq)/2)*sq*sq;
whiteToBlack = ((n/sq)*(n/sq)/2+1)*sq*sq;
} else {
whiteToWhite = ((n/sq)*(n/sq)/2)*sq*sq;
whiteToBlack = ((n/sq)*(n/sq)/2)*sq*sq;
}
if(startWhite) swap(whiteToBlack,whiteToWhite);
rep(i,0,k){
ll x1,y1,x2,y2;
tie(x1,y1,x2,y2) = v[i];
ll sz = (x2-x1)*(y2-y1);
ll numBlack = getNumBlack(x1,y1,x2,y2,sq);
if(startWhite)
numBlack = sz-numBlack;
whiteToBlack -= numBlack;
blackToBlack += numBlack;
whiteToWhite -= sz-numBlack;
blackToWhite += sz-numBlack;
}
return whiteToBlack + blackToWhite;
}
int main(){
cin.sync_with_stdio(false);
cin>>n>>k;
rep(i,0,k){
ll x1,y1,x2,y2;
cin>>x1>>y1>>x2>>y2;
--x1;--y1;
v.emplace_back(x1,y1,x2,y2);
}
/*ll numDivs = 0;
rep(i,1,n)
if(n%i==0)
numDivs++;
cout<<numDivs<<endl;*/
ll bestCost = 1e18;
rep(i,1,n){
if(n%i==0){
bestCost = min(bestCost,getCost(i,false));
bestCost = min(bestCost,getCost(i,true));
}
}
cout<<bestCost<<endl;
//cout<<getNumBlack(3,5,5,7,4)<<endl;
//return 0;
/*srand(time(NULL));
rep(i,0,1000){
ll x2 = rand()%10+1;
ll y2 = rand()%10+1;
ll x1 = rand()%x2;
ll y1 = rand()%y2;
cout<<getNumBlack(x1,y1,x2,y2,rand()%10+1)<<endl;
}*/
/*ll w = 7;
ll h = 5;
rep(i,0,10){
rep(j,0,10){
cout<<(getNumBlack(j,i,j+w,i+h,2)==(w*h/2))<<" ";
}
cout<<endl;
}*/
}
