#include <iostream>
using namespace std;
#define int long long
int n, m, q, k, a[500005], b[500005], tb[500005], sum;
signed main(){
	cin >> n >> m >> q >> k;
	while (q --){
		int op, x;
		cin >> op >> x;
		if (op == 1) a[x] ++,a[x] %= k;
		else b[x] ++,b[x] %= k;
	}
	sum = n * m;
	for (int i = 1; i <= m; i ++) tb[b[i]] ++;
	for (int i = 1; i <= n; i ++) sum -= a[i] * tb[(k - a[i]) % k];
	cout << sum;
	return 0;
}