#include <stdio.h>
#include <bits/stdc++.h>
#include <atcoder/all>
using namespace atcoder;
using mint = modint998244353;
using namespace std;
#define rep(i,n) for (int i = 0; i < (n); ++i)
#define Inf 1000000001
	 
int main(){
	
	long long N,M,X;
	cin>>N>>M>>X;
	
	vector v(M+5,vector<long long>());
	
	rep(i,N){
		long long a,b;
		cin>>a>>b;
		
		v[b].push_back(a);
	}
	vector<long long> S;
	rep(i,v.size()){
		sort(v[i].rbegin(),v[i].rend());
		if(v[i].size()>0){
			v[i][0] += X;
			rep(j,v[i].size())S.push_back(v[i][j]);
		}
	}
	
	sort(S.rbegin(),S.rend());
	
	S.insert(S.begin(),0LL);
	rep(i,S.size()-1)S[i+1] += S[i];

	long long ans = 0LL;
	int K;cin>>K;
	rep(i,K){
		int C;
		cin>>C;
		ans += S[C];
	}
	cout<<ans<<endl;
	
	return 0;
}