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);
        int prev = 0;
        long[] values = new long[n];
        for (int i = n - 1; i >= 0; i--) {
            values[i] = questions[i].value;
            if (questions[i].type != prev) {
                values[i] += x;
                prev = questions[i].type;
            }
        }
        Arrays.sort(values);
        long[] sums = new long[n + 1];
        for (int i = 1; i <= n; i++) {
            sums[i] = sums[i - 1] + values[n - i];
        }
        int k = sc.nextInt();
        long ans = 0;
        for (int i = 0; i < k; i++) {
            ans += sums[sc.nextInt()];
        }
        System.out.println(ans);
    }
    
    static class Question implements Comparable<Question> {
        int type;
        int value;
        
        public Question(int value, int type) {
            this.type = type;
            this.value = value;
        }
        
        public int compareTo(Question another) {
            if (type == another.type) {
                return value - another.value;
            } else {
                return type - another.type;
            }
        }
    }
}
    
class Scanner {
    BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
    StringTokenizer st = new StringTokenizer("");
    StringBuilder sb = new StringBuilder();
    
    public Scanner() throws Exception {
        
    }
    
    public int nextInt() throws Exception {
        return Integer.parseInt(next());
    }
    
    public long nextLong() throws Exception {
        return Long.parseLong(next());
    }
    
    public double nextDouble() throws Exception {
        return Double.parseDouble(next());
    }
    
    public String next() throws Exception {
        while (!st.hasMoreTokens()) {
            st = new StringTokenizer(br.readLine());
        }
        return st.nextToken();
    }
    
}