#include <bits/stdc++.h>
#include <atcoder/dsu>
using namespace std;
using ll = long long;
int main() {
    std::ios_base::sync_with_stdio(false);
    std::cin.tie(nullptr);
    int h, w, n;
    cin >> h >> w >> n;
    atcoder::dsu uf(h + w);
    vector<int> a(n), b(n);
    for (int i = 0; i < n; i++) {
        cin >> a[i] >> b[i];
        a[i]--, b[i]--;
        uf.merge(a[i], b[i] + h);
    }
    int cur = 0;
    vector<vector<int>> dp(2, vector<int>(w + 1, 1e9)), ep(2, vector<int>(w + 1, -1e9));
    dp[cur][0] = ep[cur][0] = 0;
    const auto G = uf.groups();
    const int K = G.size();
    for (int i = 0; i < K; i++) {
        int nxt = 1 - cur;
        for (int j = 0; j <= w; j++) dp[nxt][j] = dp[cur][j], ep[nxt][j] = ep[cur][j];
        int r = 0, c = 0;
        for (int x : G[i]) {
            r += x < h;
            c += x >= h;
        }
        for (int j = 0; j <= w; j++) {
            if (dp[cur][j] != 1e9) {
                dp[nxt][j + c] = min(dp[nxt][j + c], dp[cur][j] + r);
            }
            if (ep[cur][j] != -1e9) {
                ep[nxt][j + c] = max(ep[nxt][j + c], ep[cur][j] + r);
            }
        }
        cur = nxt;
    }
    ll ans = 0;
    for (int j = 0; j <= w; j++) {
        if (dp[cur][j] != 1e9) {
            int i = dp[cur][j];
            ans = max<ll>(ans, i * w + j * h - 2 * i * j);
        }
        if (ep[cur][j] != -1e9) {
            int i = ep[cur][j];
            ans = max<ll>(ans, i * w + j * h - 2 * i * j);
        }
    }
    cout << ans << "\n";
}