#include<bits/stdc++.h>
/*
#pragma optimize ("g",on)
#pragma GCC optimize("inline")
#pragma GCC optimize ("Ofast")
#pragma GCC optimize ("unroll-loops")
#pragma GCC optimize ("03")
#pragma GCC target ("sse,sse2,sse3,ssse3,sse4,popcnt,abm,avx2,mmx,fma,avx,tune=native")
*/
//01001101 01100001 01101011 01101000 01100001 01100111 01100001 01111001
using namespace std;
#define all(a) a.begin(), a.end()
#define rall(a) a.rbegin(), a.rend()
#define ll long long
#define pb push_back
#define sz(a) a.size()
#define nl '\n'
#define popb pop_back()
#define ld double
#define ull unsigned long long
#define ff first
#define ss second
#define fix fixed << setprecision
#define pii pair<int, int>
#define E exit (0)
#define int long long
const int inf = 1e9, N = 2e5 + 1, mod = 998244353;
vector<pii> dir = {{1, 0}, {0, 1}, {-1, 0}, {0, -1}};
main() {
//freopen("cowrect.in", "r", stdin);
//freopen("cowrect.out", "w", stdout);
ios_base::sync_with_stdio(NULL);
cin.tie(NULL);
int n, k;
cin >> n >> k;
int cnt0 = 0, cnt1 = 0;
for (int i = 1; i <= k; i++) {
int x1, y1, x2, y2;
cin >> x1 >> y1 >> x2 >> y2;
if (x1 % 2 == y1 % 2) {
cnt0++;
}else {
cnt1++;
}
}
if (k == 0) {
int mn = inf;
for (int val = 1; val < n; val++) {
if (n % val) continue;
int x = n * n / val / val;
mn = min(mn, x / 2 * val * val);
}
cout << mn;
}else {
cout << min(cnt0 + n * n / 2 - cnt1, cnt1 + n * n / 2 + 1 - cnt0);
}
}
