#include <bits/stdc++.h>
using namespace std;

long long n, k, m, x, c, s, t, z = 0;
vector<long long> a[200000];
vector<long long> b, d;

int main()
{
	cin >> n >> m >> x;

	for (int i = 0; i < n; i++) {
		cin >> s >> t;
		t--;

		a[t].push_back(s);
	}

	for (int i = 0; i < m; i++) {
		if (a[i].size() > 0) {
			sort(a[i].begin(), a[i].end());
			a[i].back() += x;

			for (long long j : a[i])
				b.push_back(j);
		}
	}

	sort(b.begin(), b.end(), greater<long long>());
	d.push_back(b[0]);

	for (int i = 1; i < b.size(); i++)
		d.push_back(d.back() + b[i]);

	cin >> k;

	for (int i = 0; i < k; i++) {
		cin >> c;

		if(c > 0)
			z += d[c - 1];
	}

	cout << z << endl;
}