#include <bits/stdc++.h>
using namespace std;
#define maxn 1005
int n, k;
int chess[maxn][maxn];
void solve_k0(){
int minimo = 999999;
for(int i = 1; i < n; i++){
if(n % i != 0) continue;
int test = i*i;
minimo = min(minimo, ((n*n/test)/2)*test);
}
cout << minimo << endl;
}
int main(){
memset(chess, 0, sizeof chess);
cin >> n >> k;
if(k == 0) solve_k0();
else{
for(int i = 0; i < k; i++){
int x, y, l, m;
cin >> x >> y;
cin >> l >> m; //8)
chess[x][y] = 1;
}
int cont_errado = 0;
for(int i = 1; i <= n; i++)
for(int j = 1; j <= n; j++)
if((i+j)%2 == chess[i][j]) cont_errado++;
cout << min(cont_errado, n*n - cont_errado) << endl;
}
return 0;
}
