import java.io.*;
import java.util.*;

public class Main {
    public static void main(String[] args) throws Exception {
        Scanner sc = new Scanner();
        int n = sc.nextInt();
        int m = sc.nextInt();
        int x = sc.nextInt();
        Question[] questions = new Question[n];
        for (int i = 0; i < n; i++) {
            questions[i] = new Question(sc.nextInt(), sc.nextInt());
        }
        Arrays.sort(questions, new Comparator<Question>() {
            public int compare(Question q1, Question q2) {
                if (q1.type == q2.type) {
                    return q2.value - q1.value;
                } else {
                    return q1.type - q2.type;
                }
            }
        });
        int prev = 0;
        for (Question q : questions) {
            if (q.type != prev) {
                prev = q.type;
                q.value += x;
            }
        }
        Arrays.sort(questions, new Comparator<Question>() {
            public int compare(Question q1, Question q2) {
                return q2.value - q1.value;
            }
        });
        long[] sums = new long[n + 1];
        for (int i = 0; i < n; i++) {
            sums[i + 1] = sums[i] + questions[i].value;
        }
        long ans = 0;
        int k = sc.nextInt();
        for (int i = 0; i < k; i++) {
            ans += sums[sc.nextInt()];
        }
        System.out.println(ans);
    }
    
    static class Question {
        int value;
        int type;
        
        public Question(int value, int type) {
            this.value = value;
            this.type = type;
        }
    }
}
class Scanner {
    BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
    StringTokenizer st = new StringTokenizer("");
    
    public Scanner() throws Exception {
        
    }
    
    public int nextInt() throws Exception {
        return Integer.parseInt(next());
    }
    
    public long nextLong() throws Exception {
        return Long.parseLong(next());
    }
    
    public String nextLine() throws Exception {
        return br.readLine();
    }
    
    public String next() throws Exception {
        if (!st.hasMoreTokens()) {
            st = new StringTokenizer(br.readLine());
        }
        return st.nextToken();
    }
}