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

int n, k;
long long m, x, s, t, z = 0;
vector<long long> a[200000];
long long c[200000], d[200001];
priority_queue<pair<long long, int>> Q1, Q2;

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());
			Q2.push({ a[i].back(), i });
			a[i].pop_back();
		}
	}

	cin >> k;

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

	sort(c, c + k);
	int j = 0, u = k;

	for (int i = 0; i < k; i++) {
		while (j <= c[i]) {
			d[j] = u;
			j++;
		}

		u--;
	}

	long long p1 = 0, p2 = 0, z1 = -1, z2 = -1;
	int w = 1, y = 0, q1, q2;

	while (w <= c[k - 1]) {
		if (!Q1.empty()) {
			p1 = Q1.top().first;
			q1 = Q1.top().second;
			Q1.pop();
			z1 = p1;
		}

		if (!Q2.empty()) {
			p2 = Q2.top().first;
			q2 = Q2.top().second;
			Q2.pop();
			z2 = p2 + x;
		}

		if (z1 >= z2) {
			z += z1 * d[w];
			z1 = 0;

			if (a[q1].size() > 0) {
				Q1.push({ a[q1].back(), q1 });
				a[q1].pop_back();
			}

			if(z2 > 0)
				Q2.push({ p2, q2 });
		}
		else {
			z += z2 * d[w];
			y++;
			z2 = 0;

			if (a[q2].size() > 0) {
				Q1.push({ a[q2].back(), q2 });
				a[q2].pop_back();
			}

			if(z1 > 0)
				Q1.push({ p1, q1 });
		}

		w++;
	}

	cout << z << endl;
}