#include <bits/stdc++.h>
using i64 = long long;
#ifdef DEBUG
#include "../../../debug.h"
#else
#define debug(...) void(23)
#endif
i64 get(i64 a, i64 b, i64 len) {
i64 ans = 0;
i64 ma = a % (2 * len);
i64 mb = b % (2 * len);
i64 da = a / (2 * len);
i64 db = b / (2 * len);
ans += da * db * len * len * 2;
ans += mb * da * len;
ans += ma * db * len;
ans += std::max(0LL, mb - len) * std::min(len, ma);
ans += std::max(0LL, ma - len) * std::min(len, mb);
debug(a, b, len, ans);
return ans;
}
i64 count_good(i64 a, i64 b, i64 c, i64 d, i64 len) {
return get(c, d, len)
- get(a, d, len)
- get(c, b, len)
+ get(a, b, len);
}
int main() {
std::ios::sync_with_stdio(false);
std::cin.tie(nullptr);
i64 N, K;
std::cin >> N >> K;
std::vector<i64> A(K), B(K), C(K), D(K);
for (int i = 0; i < K; ++i) {
std::cin >> A[i] >> B[i] >> C[i] >> D[i];
--A[i], --B[i];
}
i64 ans = 2 * N * N;
for (i64 k = 1; k < N; ++k) {
if (N % k != 0) {
continue;
}
i64 now = N * N - count_good(0, 0, N, N, k);
for (int i = 0; i < K; ++i) {
i64 x = count_good(A[i], B[i], C[i], D[i], k);
debug(A[i], B[i], C[i], D[i], x);
now -= ((C[i] - A[i]) * (D[i] - B[i]) - x);
now += x;
}
debug(k, now);
ans = std::min(ans, std::min(now, N * N - now));
}
std::cout << ans << '\n';
return 0;
}
