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

int main()
{
	int N, M;
	long long X;
	cin >> N >> M >> X;
	typedef pair<int, int> P;
	vector<P> ab( N );
	for( int i = 0; i < N; i++ ) {
		int A, B;
		cin >> A >> B;
		ab[i] = P( A, B );
	}

	sort( ab.begin(), ab.end(), greater<P>() );
	set<int> st;
	for( int i = 0; i < N; i++ ) {
		if( i == 0 ) st.insert( ab[i].second );
		else if( (int)st.size() < M ) {
			for( int j = i + 1; j < N; j++ ) {
				if( st.count( ab[j].second ) == 0 ) {
					if( ab[i].first + X * st.size() < ab[j].first + X * (st.size() + 1) ) {
						st.insert( ab[j].second );
						swap( ab[i], ab[j] );
						i = j;
						break;
					}
				}
			}
		}
	}
	vector<long long> acc( N + 1 );
	vector<int> b( N + 1 );
	st.clear();
	for( int i = 0; i < N; i++ ) {
		acc[i + 1] = acc[i] + ab[i].first;
		st.insert( ab[i].second );
		b[i + 1] = st.size();
	}
	long long ans = 0;
	int K;
	cin >> K;
	for( int i = 0; i < K; i++ ) {
		int C;
		cin >> C;
		ans += acc[C] + X * b[C];
	}

	cout << ans << endl;
}