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

int main()
{
    int n, m, x;
    cin >> n >> m >> x;
    vector<vector<int>> score(m);
    for (int i = 0; i < n; i++)
    {
        int a, b;
        cin >> a >> b;
        b--;
        score.at(b).push_back(a);
    }
    vector<int> scores;
    for (int i = 0; i < m; i++)
    {
        if (score.at(i).empty())
        {
            continue;
        }
        sort(score.at(i).rbegin(), score.at(i).rend());
        score.at(i).at(0) += x;
        for (auto &&s : score.at(i))
        {
            scores.push_back(s);
        }
    }
    sort(scores.rbegin(), scores.rend());
    vector<int64_t> scores_sum(n + 1);
    for (int i = 0; i < n; i++)
    {
        scores_sum.at(i + 1) = scores_sum.at(i) + scores.at(i);
    }
    int64_t ans = 0;
    int k;
    cin >> k;
    for (int i = 0; i < k; i++)
    {
        int c;
        cin >> c;
        ans += scores_sum.at(c);
    }
    cout << ans << endl;
    return 0;
}