#include <iostream>
#include <climits>
#include <tuple>
#include <vector>
#pragma GCC optimize("Ofast")
#pragma GCC target("avx,avx2,fma")
#define MN 167171
using namespace std;
using ll = long long;
ll n, k;
tuple<int, int, int, int> R[MN];
ll P[MN], D[MN];
ll P2[MN], D2[MN];
static inline ll calc(ll a, ll b, ll l) {
if(P[a] == 0 && P[b] == 0)
return ((D[a] * D[b] + 1) >> 1) * l * l;
if(P[a]) {
ll nrseg;
if((D[a] & 1) == 0) {
if(P2[b] <= l) nrseg = D2[b] * l + P2[b];
else nrseg = (D2[b] + 1) * l;
} else {
if(P2[b] <= l) nrseg = D2[b] * l;
else nrseg = (D2[b] - 1) * l + P2[b];
}
return calc(a - P[a], b, l) + P[a] * nrseg;
}
return calc(b, a, l);
}
ll sol(ll l) {
for(int i = 1; i <= n; ++i) {
D[i] = D[i-1];
P[i] = P[i-1] + 1;
if(P[i] == l) ++D[i], P[i] = 0;
D2[i] = D2[i-1];
P2[i] = P2[i-1] + 1;
if(P2[i] == (l << 1)) ++D2[i], P2[i] = 0;
}
ll arie = ((n / l) * (n / l) + 1) / 2 * l * l, selec;
for(int i = 1; i <= k; ++i) {
auto &[a, b, c, d] = R[i];
selec = calc(c, d, l) + calc(a-1, b-1, l) - calc(c, b-1, l) - calc(a-1, d, l);
arie += (c - a + 1) * (d - b + 1) - 2 * selec;
}
return min(arie, 1ll * n * n - arie);
}
int main() {
cin.tie(0);
ios_base::sync_with_stdio(0);
cin >> n >> k;
for(int i = 1, a, b, c, d; i <= k; ++i)
cin >> a >> b >> c >> d, R[i] = make_tuple(a, b, c, d);
ll re = LLONG_MAX;
for(int i = 1; i < n; ++i)
if(n % i == 0) re = min(re, sol(i));
cout << re << "\n";
return 0;
}
