#include <bits/stdc++.h>
using namespace std;
#define int long long
int row[1000100];
int col[1000100];

signed main(){
	int W,H;
	cin >> W >> H;
	int N;
	cin >> N;
	int ans = 0;
	for(int i = 0 ; i < N ; i++){
		int x,y;
		cin >> x >> y;
		row[y]++;
		col[x]++;
	}
	int r = 0;
	for(int i = 0 ; i <= 1000000 ; i++){
		if( row[i] ) ans += W - row[i], r++;
	}
	for(int i = 0 ; i <= 1000000 ; i++){
		if( col[i] ) ans += H - col[i] - r;
	}
	cout << ans+N << endl;
	
}