#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
#define MASK(i) (1LL << (i))
#define GETBIT(mask, i) (((mask) >> (i)) & 1)
#define ALL(v) (v).begin(), (v).end()
ll max(ll a, ll b){return (a > b) ? a : b;}
ll min(ll a, ll b){return (a < b) ? a : b;}
ll gcd(ll a, ll b){return __gcd(a, b);}
ll LASTBIT(ll mask){return (mask) & (-mask);}
int pop_cnt(ll mask){return __builtin_popcountll(mask);}
int ctz(ll mask){return __builtin_ctzll(mask);}
int logOf(ll mask){return __lg(mask);}
mt19937_64 rng(chrono::high_resolution_clock::now().time_since_epoch().count());
ll rngesus(ll l, ll r){return l + (ull) rng() % (r - l + 1);}
template <class T1, class T2>
bool maximize(T1 &a, T2 b){
if (a < b) {a = b; return true;}
return false;
}
template <class T1, class T2>
bool minimize(T1 &a, T2 b){
if (a > b) {a = b; return true;}
return false;
}
template <class T>
void printArr(T& container, string separator = " ", string finish = "\n"){
for(auto item: container) cout << item << separator;
cout << finish;
}
template <class T>
void remove_dup(vector<T> &a){
sort(ALL(a));
a.resize(unique(ALL(a)) - a.begin());
}
const ll INF = 1e18 + 69;
ll count_black_chess(ll k){
return k * k / 2;
}
ll count_stuff(int i, int x, int y){
if (min(x, y) == 0) return 0;
int _x = x / i, _y = y / i;
ll ans = 1LL * _x * _y / 2 * i * i;
ans += 1LL * ((_x + _y % 2) / 2) * (y - _y * i) * i;
ans += 1LL * ((_y + _x % 2) / 2) * (x - _x * i) * i;
ans += 1LL * ((_x + _y) % 2) * (x - _x * i) * (y - _y * i);
return ans;
}
ll go(int i, vector<array<int, 4>> &arr){ // count number of overlapped black squares
ll ans = 0;
for(auto j: arr){
ans += count_stuff(i, j[2], j[3]);
ans -= count_stuff(i, j[0]-1, j[3]);
ans -= count_stuff(i, j[2], j[1]-1);
ans += count_stuff(i, j[0]-1, j[1]-1);
}
return ans;
}
void solve(){
int n, k; cin >> n >> k;
vector<array<int, 4>> arr(k);
for(int i = 0; i < k; ++i) for(int j = 0; j < 4; ++j) cin >> arr[i][j];
ll tot_black = 0;
for(auto &i: arr) {
tot_black += 1LL * abs(i[3] - i[1] + 1) * abs(i[2] - i[0] + 1);
}
ll ans = INF;
for(int i = 1; i < n; ++i){
if (n % i == 0){
ll cur = go(i, arr);
ll black_cnt = 1LL * i * i * count_black_chess(n / i);
minimize(ans, (black_cnt - cur) + (tot_black - cur));
cur = tot_black - cur;
black_cnt = 1LL * n * n - black_cnt;
minimize(ans, (black_cnt - cur) + (tot_black - cur));
}
}
cout << ans << "\n";
}
int main(void){
ios::sync_with_stdio(0); cin.tie(0); cout.tie(0);
clock_t start = clock();
solve();
cerr << "Time elapsed: " << clock() - start << "ms!\n";
return 0;
}
