#include <iostream>
#include <algorithm>
#include <vector>
using namespace std;
using ll = long long;
struct el {
int a, b, c, d;
};
vector<ll> dv;
vector<el> points;
ll ans;
ll prefans(ll x, ll y, ll k, ll f)
{
ll ans;
ll ab = y / k, a;
a = (ab + 1) / 2;
a *= k;
if (ab % 2 == 0)
a += y % k;
if (x <= k)
ans = x * a;
else
{
ll aa = y - a;
ll q = x / k;
ans = aa * (q / 2) * k;
ans += a * ((q + 1) / 2) * k;
if (q % 2)
ans += aa * (x % k);
else ans += a * (x % k);
}
if (f == 1)
return ans;
else return x * y - ans;
}
long long NumWhite(long long mini, long long minj, long long maxi, long long maxj, long long len)
{
if (!mini) mini=1;
if (!minj) minj=1;
if (mini==1 && minj==1)
{
return prefans(maxi, maxj, len, 1);
long long ans=0, i=maxi, j=maxj;
ans+=len*len*(((i/len)*(j/len)+1)/2);
if ((i/len)%2)
ans+=(i%len)*((j/len)/2)*len;
else
ans+=(i%len)*((j/len+1)/2)*len;
if ((j/len)%2)
ans+=(j%len)*((i/len)/2)*len;
else
ans+=(j%len)*((i/len+1)/2)*len;
if ((i/len)%2==(j/len)%2)
ans+=(i%len)*(j%len);
return ans;
}
return NumWhite(1, 1, maxi, maxj, len)-
NumWhite(1, 1, maxi, minj-1, len)-NumWhite(1, 1, mini-1, maxj, len)+
NumWhite(1, 1, mini-1, minj-1, len);
}
int main()
{
ll n, k;
cin >> n >> k;
ans = n * n;
for (int i = 1; i < n; i++)
if (n % i == 0)dv.push_back(i);
for (int i = 0; i < k; i++)
{
int a, b, c, d;
cin >> a >> b >> c >> d;
points.push_back({ a,b,c,d });
}/*
for (auto p : points)
cerr << p.first << ' ' << p.second << '\n';*/
for (ll d : dv)
{
ll blackans;
ll q = n / d;
if (q % 2)
blackans = (n * n - d * d) / 2 + d * d;
else blackans = n * n / 2;
ll whiteans = n * n - blackans;
blackans = n * n - NumWhite(1, 1, n, n, d);
whiteans = NumWhite(1, 1, n, n, d);
//cerr << blackans << ' ' << whiteans << " 1, 1, " << n << ", " << n << " " << NumWhite(1, 1, n, n, d) << '\n';
for (auto p : points)
{
blackans -= (p.d - p.b + 1) * (p.c - p.a + 1) - NumWhite(p.a, p.b, p.c, p.d, d);
whiteans -= NumWhite(p.a, p.b, p.c, p.d, d);
whiteans += (p.d - p.b + 1) * (p.c - p.a + 1) - NumWhite(p.a, p.b, p.c, p.d, d);
blackans += NumWhite(p.a, p.b, p.c, p.d, d);
//blackans += prefans(p.c, p.d, d, 1) - prefans(p.a - 1, p.d, d, 1) - prefans(p.c, p.b - 1, d, 1) + 2 * prefans(p.a - 1, p.b - 1, d, 1);
//whiteans += prefans(p.c, p.d, d, 0) - prefans(p.a - 1, p.d, d, 0) - prefans(p.c, p.b - 1, d, 0) + 2 * prefans(p.a - 1, p.b - 1, d, 0);
}
//cerr << blackans << ' ' << whiteans << '\n';
ans = min(ans, min(blackans, whiteans));
}
cout << ans;
return 0;
}
