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

int main()
{
	int N, M;
	long long X;
	cin >> N >> M >> X;
	vector<vector<int>> g( M );
	for( int i = 0; i < N; i++ ) {
		int A, B;
		cin >> A >> B;
		B--;
		g[B].push_back( A );
	}
	int K;
	cin >> K;
	vector<int> C( K );
	for( int i = 0; i < K; i++ ) cin >> C[i];

	for( int i = 0; i < M; i++ ) {
		if( g[i].size() == 0 ) continue;
		sort( g[i].begin(), g[i].end(), greater<int>() );
	}
	vector<long long> v;
	for( int i = 0; i < M; i++ ) {
		int n = g[i].size();
		if( n == 0 ) continue;
		for( int j = 0; j < n; j++ ) {
			long long a = g[i][j];
			if( j == 0 ) a += X;
			v.push_back( a );
		}
	}
	sort( v.begin(), v.end(), greater<long long>() );
	vector<long long> acc( N + 1 );
	for( int i = 0; i < N; i++ ) acc[i + 1] = acc[i] + v[i];
	long long ans = 0;
	for( int i = 0; i < K; i++ ) {
		ans += acc[ C[i] ];
	}

	cout << ans << endl;
}