#include<iostream>
#include<string>
#include<cstdio>
#include<vector>
#include<cmath>
#include<algorithm>
#include<functional>
#include<iomanip>
#include<queue>
#include<ciso646>
#include<random>
#include<map>
#include<set>
#include<complex>
#include<bitset>
#include<stack>
#include<unordered_map>
using namespace std;
typedef long long ll;
typedef unsigned int ui;
const ll mod = (ll)(1e+9) + 7;
const ll INF = (ll)1000000007 * 1000000007;
typedef pair<int, int> P;
#define stop char nyaa;cin>>nyaa;
#define rep(i,n) for(int i=0;i<n;i++)
#define per(i,n) for(int i=n-1;i>=0;i--)
#define Rep(i,sta,n) for(int i=sta;i<n;i++)
#define rep1(i,n) for(int i=1;i<=n;i++)
#define per1(i,n) for(int i=n;i>=1;i--)
#define Rep1(i,sta,n) for(int i=sta;i<=n;i++)
typedef long double ld;
typedef complex<ld> Point;
const ld eps = 1e-8;
const ld pi = acos(-1.0);
typedef pair<ll, ll> LP;
typedef pair<ld, ld> LDP;
int w, h, n;
map<int, bool> ux, uy;
map<P, bool> u;
int s[100], k[100];
ll out = 0;
int main(){
	cin >> w >> h >> n;
	rep(i, n) {
		cin >> s[i] >> k[i];
		if (ux[s[i]]) {
			out--;
		}
		else {
			ux[s[i]] = true;
			out += h - 1;
		}
		if (uy[k[i]]) {
			out--;
		}
		else {
			uy[k[i]] = true;
			out += w - 1;
		}
		u[{s[i], k[i]}] = true;
	}
	rep(i, n) {
		Rep(j, i + 1, n) {
			if (!u[{s[i], k[j]}]) {
				u[{s[i], k[j]}] = true;
				out--;
			}
			if (!u[{s[j], k[i]}]) {
				u[{s[j], k[i]}] = true;
				out--;
			}
		}
	}
	cout << out << endl;
	return 0;
}