#include <bits/stdc++.h>
#include <atcoder/dsu>

int main() {
	int H, W, N;
	std::cin >> H >> W >> N;
	atcoder::dsu uf(H + W);
	for (int i = 0; i < N; i++) {
		int A, B;
		std::cin >> A >> B;
		A--; B--;
		uf.merge(A, H + B);
	}
	std::vector<std::vector<int>> g = uf.groups();
	int L = g.size();
	std::vector<int> c(L), d(L);
	for (int i = 0; i < L; i++) {
		for (int u: g[i]) {
			if (u < H) c[i]++;
			else d[i]++;
		}
	}
	int H_ = H / 2;
	std::vector<int> dp(H_ + 1, -1);
	dp[0] = 0;
	for (int i = 0; i < L; i++) {
		for (int j = H_; j >= 0; j--) {
			if (dp[j] != -1 && j + c[i] <= H_) {
				dp[j + c[i]] = std::max(dp[j + c[i]], dp[j] + d[i]);
			}
		}
	}
	int ans = 0;
	for (int i = 0; i <= H_; i++) {
		if (dp[i] != -1) ans = std::max(ans, i * (W - dp[i]) + (H - i) * dp[i]);
	}
	std::cout << ans << '\n';
}