#include<bits/stdc++.h>
using namespace std;
long long calc(long long x1, long long x2, long long y1, long long y2, long long k) {
long long br1 = (x2/(2*k))*k+min(k-1,x2%(2*k))+1;
if(x1 > 0) {
x1--;
br1-=(x1/(2*k))*k+min(k-1,x1%(2*k))+1;
}
else {
x1--;
}
long long br2 = (y2/(2*k))*k+min(k-1,y2%(2*k))+1;
if(y1 > 0) {
y1--;
br2-=(y1/(2*k))*k+min(k-1,y1%(2*k))+1;
}
else {
y1--;
}
return br1*br2+(x2-x1-br1)*(y2-y1-br2);
}
int main()
{
ios_base::sync_with_stdio(false);
cin.tie(NULL);
cout.tie(NULL);
long long n,k,x1,y1,x2,y2,ans = LLONG_MAX;
cin >> n >> k;
vector<pair<long long,long long>> haha(0);
vector<pair<long long,long long>> bruh(0);
for(long long i = 0; i < k; i++) {
cin >> x1 >> y1 >> x2 >> y2;
haha.push_back({x1-1,y1-1});
bruh.push_back({x2-1,y2-1});
}
for(long long i = 1; i < n; i++) {
if(n%i == 0) {
long long br = (((n/i)*(n/i)+1)/2)*i*i;
for(long long j = 0; j < k; j++) {
long long c = (bruh[j].second-haha[j].second+1)*(bruh[j].first-haha[j].first+1)-2*calc(haha[j].first,bruh[j].first,haha[j].second,bruh[j].second,i);
br+=c;
}
ans = min(ans,br);
br = (((n/i)*(n/i))/2)*i*i;
for(long long j = 0; j < k; j++) {
long long c = (bruh[j].second-haha[j].second+1)*(bruh[j].first-haha[j].first+1)-2*calc(haha[j].first,bruh[j].first,haha[j].second,bruh[j].second,i);
br-=c;
}
ans = min(ans,br);
}
}
cout << ans;
return 0;
}
