#include <bits/stdc++.h>
#define FOR(i, a, b) for (int i = (a); i <= (b); ++i)
#define FORD(i, a, b) for (int i = (a); i >= (b); --i)
#define REP(i, a) for (int i = 0; i < (a); ++i)
#define DEBUG(x) { cerr << #x << '=' << x << endl; }
#define Arr(a, l, r) { cerr << #a << " = {"; FOR(_, l, r) cerr << ' ' << a[_]; cerr << "}\n"; }
#define N 1001000
#define pp pair<int, int>
#define endl '\n'
#define IO ios::sync_with_stdio(false); cin.tie(NULL); cout.tie(NULL)
#define taskname ""
#define bit(S, i) (((S) >> (i)) & 1)
using namespace std;
long long n, k, xx1[N], xx2[N], xy1[N], xy2[N];
long long cal(int l, int color, int x1, int y1, int x2, int y2) {
if (x2 < x1 || y2 < y1) return 0;
int mx1 = (x1 - 1 + l) / l * l, mx2 = (x2 + 1) / l * l - 1;
int my1 = (y1 - 1 + l) / l * l, my2 = (y2 + 1) / l * l - 1;
if (x1 / l == x2 / l) {
if (y1 / l == y2 / l) {
if (color ^ (((x1 / l) % 2) == (y1 / l) % 2)) return - 1ll * (x2 - x1 + 1) * (y2 - y1 + 1);
return 1ll * (x2 - x1 + 1) * (y2 - y1 + 1);
}
if (my1 == y1 && my2 == y2) {
int sz = (y2 + 1 - y1) / l;
if (sz % 2 == 0) return 0;
if (color ^ (((x1 / l) % 2) == (y1 / l) % 2)) return - 1ll * (x2 - x1 + 1) * l;
return 1ll * (x2 - x1 + 1) * l;;
}
return cal(l, color, x1, y1, x2, my1 - 1)
+ cal(l, color, x1, my1, x2, my2)
+ cal(l, color, x1, my2 + 1, x2, y2);
}
if (mx1 == x1 && mx2 == x2 && y1 == my1 && y2 == my2) {
int sz = (y2 + 1 - y1) / l * (x2 + 1 - x1) / l;
if (sz % 2 == 0) return 0;
if (color ^ (((x1 / l) % 2) == (y1 / l) % 2)) return - 1ll * l * l;
return l * l;
}
return cal(l, color, x1, y1, mx1 - 1, y2)
+ cal(l, color, mx1, y1, mx2, y2)
+ cal(l, color, mx2 + 1, y1, x2, y2);
}
long long solve(int l, int color) {// color = 0 -> Top-left is black
long long ans = ((1ll * (n / l) * (n / l) + 1 - color) / 2) * l * l ;
/*REP(i, k) {
if (color ^ (((xx1[i] / l) % 2) == (xy1[i] / l) % 2)) ans--;
else ans++;
}*/
REP(i, k) {
ans += cal(l, color, xx1[i], xy1[i], xx2[i], xy2[i]);
}
return ans;
}
int main() {
#ifdef NERO
freopen("test.inp","r",stdin);
freopen("test.out","w",stdout);
clock_t stime = clock();
#endif //NERO
scanf("%d %d", &n, &k);
long long ans = 1e10;
REP(i, k) scanf("%d %d %d %d", &xx1[i], &xy1[i], &xx2[i], &xy2[i]);
REP(i, k) xx1[i]--,xx2[i]--,xy1[i]--,xy2[i]--;
FOR(i, 1, sqrt(n)) if (n % i == 0) {
ans = min(ans, solve(i, 0));
ans = min(ans, solve(i, 1));
if (i != 1) ans = min(ans, solve(n / i, 0));
if (i != 1) ans = min(ans, solve(n / i, 1));
}
printf("%lld", ans);
#ifdef NERO
clock_t etime = clock();
cerr << "Execution time: " << (etime - stime) / CLOCKS_PER_SEC * 1000 << " ms.";
#endif // NERO
}
