#include<bits/stdc++.h>
#define ll long long
#define TASK "bai6D"
#define endl '\n'
 
using namespace std;
 
vector<ll> row, col;
ll m, n, k;
 
int main() {
	ios_base::sync_with_stdio(0);
	cin.tie(0); cout.tie(0);
	// freopen(TASK".inp", "r", stdin);
	// freopen(TASK".out", "w", stdout);
 
	cin >> m >> n >> k;
	k *= 4;
	for (ll x, y, i = 0; i < k; i++) {
		cin >> x >> y;
		row.push_back(x);
		col.push_back(y);
	}
	sort(row.begin(), row.end());
	sort(col.begin(), col.end());
 
	ll rowLine = row[k/2] - row[k/2 - 1];
	ll colLine = col[k/2] - col[k/2 - 1];
 
	cout << rowLine * colLine;
 
 
	cerr << 1.0 * clock() / 1000 << endl;
	// for (auto x : prime) cerr << x << " ";
 
	return 0;
}

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MTAgNCAxCjIgMQo3IDQKNiAyCjggMw==

10 4 1
2 1
7 4
6 2
8 3