#include <iostream>
#include <algorithm>
using namespace std;

pair<int, int> p[200009];
bool vs[200009];
long long s[200009];

int main()
{
	ios::sync_with_stdio(false);
	cin.tie(0);
	int n, m, x; cin >> n >> m >> x;
	for (int i = 1; i <= n; i++)
		cin >> p[i].first >> p[i].second;
	sort(p + 1, p + n + 1); reverse(p + 1, p + n + 1);
	for (int i = 1; i <= n; i++) {
		if (!vs[p[i].second]) {
			vs[p[i].second] = true;
			p[i].first += x;
		}
	}
	sort(p + 1, p + n + 1); reverse(p + 1, p + n + 1);
	for (int i = 1; i <= n; i++)
		s[i] = s[i - 1] + p[i].first;
	long long ans = 0;
	int k; cin >> k;
	for (int i = 0; i < k; i++) {
		int a; cin >> a;
		ans += s[a];
	}
	cout << ans << '\n';
	return 0;
}