#include <vector>
#include <queue>
#include <deque>
#include <stack>
#include <algorithm>
#include <functional>
#include <iostream>
#include <cstdio>
#include <cmath>
#include <cstdlib>
#include <ctime>
#include <cctype>
#include <string>

using namespace std;

typedef long long ll;

int mark[1000001];
int num[1000001];
int main() {
  ll w;
  cin >> w;
  ll h;
  cin >> h;
  int n;
  cin >> n;
  int s[n], k[n];
  for (int i = 0; i < n; i++) cin >> s[i] >> k[i];

  int markt[n];
  ll mcnt = w, ncnt = 0;
  for (int i = 0; i < n; i++) {
    if (!mark[s[i]]) {
      markt[w-mcnt] = s[i];
      mcnt--;
    }
    if (!num[k[i]]) ncnt++;
    mark[s[i]]++;
    num[k[i]]++;
  }
  
  ll ans = 0;
  for (int i = 0; i < w-mcnt; i++) {
    ans += h-mark[markt[i]];
  }
  ans += mcnt*ncnt;

  cout << ans << endl;
}