#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<LL> V(N), G(N);
	rep(i,N) cin >> V[i] >> G[i];
	int K;
	cin >> K;
	vector<int> p(K);
	rep(i,K) cin >> p[i];
	if(N >= 10){
		cout << 0 << endl;
		return 0;
	}
	vector<int> per(N);
	LL ans = 0;
	rep(i,N) per[i] = i;
	do{
		LL res = 0;
		rep(i,K){
			LL kind = 0;
			vector<bool> solved(M);
			rep(j,p[i]){
				int num = per[j];
				res += V[num];
				if(!solved[G[num]]) kind++;
				solved[G[num]] = true;
			}
			res += X * kind;
		}
		ans = max(ans,res);

	}while(next_permutation(per.begin(),per.end()));
	cout << ans << endl;

	return 0;
}