#include <algorithm>
#include <iostream>
#include <vector>
using namespace std;


int main() {
    cin.tie(nullptr), ios::sync_with_stdio(false);
    int N, M;
    int X;
    cin >> N >> M >> X;
    vector<vector<int>> genre2quals(M);
    for (int i = 0; i < N; ++i) {
        int a, b;
        cin >> a >> b;
        genre2quals[b - 1].push_back(a);
    }

    vector<int> vals;
    for (auto &quals : genre2quals) {
        sort(quals.begin(), quals.end());
        if (quals.empty()) continue;
        quals.back() += X;
        vals.insert(vals.end(), quals.begin(), quals.end());
    }
    sort(vals.rbegin(), vals.rend());

    vector<int> nb_solver(N + 1);
    int K;
    cin >> K;
    while (K--) {
        int c;
        cin >> c;
        nb_solver[0]++;
        nb_solver[c]--;
    }

    long long ret = 0;
    for (int i = 0; i < N; i++) {
        ret += (long long)(vals[i]) * nb_solver[i];
        nb_solver[i + 1] += nb_solver[i];
    }
    cout << ret << '\n';
}