#include <bits/stdc++.h>
using namespace std;

class UnionFind{
    public:
    vector<int> par,siz;
 
    void make(int N){
        par.resize(N,-1);
        siz.resize(N,1);
    }
 
    int root(int x){
        if(par.at(x) == -1) return x;
        else return par.at(x) = root(par.at(x));
    }
 
    void unite(int u, int v){
        u = root(u),v = root(v);
        if(u == v) return;
        if(siz.at(u) < siz.at(v)) swap(u,v);
 
        par.at(v) = u;
        siz.at(u) += siz.at(v);
    }
 
    bool issame(int u, int v){
        if(root(u) == root(v)) return true;
        else return false;
    }
};

int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);

    int H,W,N; cin >> H >> W >> N;
    UnionFind uf; uf.make(H+W);
    while(N--){
        int a,b; cin >> a >> b;
        a--; b--; b += H;
        uf.unite(a,b);
    }
    vector<pair<int,int>> need(H+W);
    for(int i=0; i<H+W; i++){
        if(i < H) need.at(uf.root(i)).first++;
        else need.at(uf.root(i)).second++;
    }
    auto update = [&](pair<int,int> &a,pair<int,int> b,int c) -> void {
        auto &[mina,maxa] = a;
        auto &[minb,maxb] = b;
        if(b == make_pair(W*2,-W*2)) return;
        mina = min(mina,minb+c);
        maxa = max(maxa,maxb+c);
    };
    vector<pair<int,int>> dp(H+1,{W*2,-W*2});
    dp.at(0) = {0,0};
    for(auto &[r,c] : need){
        if(r+c == 0) continue;
        for(int i=H-r; i>=0; i--) update(dp.at(i+r),dp.at(i),c);
    }
    int answer = 0;
    for(int i=0; i<=H; i++){
        auto &[minv,maxv] = dp.at(i);
        if(minv != W*2) answer = max(answer,(-2*i+H)*minv+i*W);
        if(maxv != -W*2) answer = max(answer,(-2*i+H)*maxv+i*W);
    }
    cout << answer << endl;
}