#include <bits/stdc++.h>
#pragma GCC optimize("Ofast")
#define _GLIBCXX_DEBUG
using namespace std;
using std::cout;
using std::cin;
using std::endl;
using ll=long long;
using ld=long double;
ll ILL=1167167167167167167;
const int INF=2100000000;
const ll mod=998244353;
#define rep(i,a) for (ll i=0;i<a;i++)
template<class T> using _pq = priority_queue<T, vector<T>, greater<T>>;
template<class T> ll LB(vector<T> &v,T a){return lower_bound(v.begin(),v.end(),a)-v.begin();}
template<class T> ll UB(vector<T> &v,T a){return upper_bound(v.begin(),v.end(),a)-v.begin();}
template<class T> bool chmin(T &a,const T &b){if(a>b){a=b;return 1;}else return 0;}
template<class T> bool chmax(T &a,const T &b){if(a<b){a=b;return 1;}else return 0;}
template<class T> void So(vector<T> &v) {sort(v.begin(),v.end());}
template<class T> void Sore(vector<T> &v) {sort(v.begin(),v.end(),[](T x,T y){return x>y;});}
void yneos(bool a){if(a) cout<<"Yes\n"; else cout<<"No\n";}



//  rainy ~ 雨に打たれて ~
int main() {
	ios::sync_with_stdio(false);
	cin.tie(nullptr);
	
	ll N,M,X;
	cin>>N>>M>>X;
	vector<vector<ll>> G(M);
	vector<ll> p;
	rep(i,N){
		ll a,b;
		cin>>a>>b;
		b--;
		G[b].push_back(a);
	}
	rep(i,M){
		Sore(G[i]);
		if(G[i].size()==0) continue;
		G[i][0]+=X;
		rep(j,G[i].size()){
			p.push_back(G[i][j]);
		}
	}
	Sore(p);
	rep(i,N-1) p[i+1]+=p[i];
	int K;
	cin>>K;
	ll ans=0;
	rep(i,K){
		int a;
		cin>>a;
		a--;
		if(a!=-1) ans+=p[a];
	}
	cout<<ans<<"\n";
}