#include <bits/stdc++.h>
#define rep(i,n) for(int i=0; i<(int)(n); i++)

using namespace std;
using LL = long long;

int main(){
	int N, M;
	LL X;
	cin >> N >> M >> X;
	vector<vector<LL>> G(M);
	rep(i,N){
		LL v, g;
		cin >> v >> g;
		g--;
		G[g].emplace_back(v);
	}
	int K;
	cin >> K;
	vector<int> p(K);
	rep(i,K) cin >> p[i];
	rep(i,M) sort(G[i].begin(),G[i].end(),greater<LL>());
	rep(i,M) if(G[i].size()) G[i][0] += X;
	vector<LL> V;
	rep(i,M){
		rep(j,G[i].size()) V.emplace_back(G[i][j]);
	}
	sort(V.begin(),V.end(),greater<LL>());
	vector<LL> sum(N+1);
	rep(i,N) sum[i+1] = sum[i] + V[i];
	LL ans = 0;
	rep(i,K) ans += sum[p[i]];
	cout << ans << endl;

	return 0;
}