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

#define ll long long
#define rep(i, n) for (int i = 0; i < (n); i++)
#define P pair<int, int>
#define LP pair<ll, ll>
#define fi first
#define se second
#define pb push_back
#define eb emplace_back
#define all(s) s.begin(), s.end()
#define rall(s) s.rbegin(), s.rend()
template<class T>
void chmax(T& a, T b) { a = max(a, b); };
template<class T>
void chmin(T& a, T b) { a = min(a, b); };

int main() {
  int n, m; ll x;
  cin >> n >> m >> x;
  vector<int> t[200005];
  rep(i,n) {
    int a, b;
    cin >> a >> b;
    b--;
    t[b].pb(a);
  }
  vector<int> ord;
  rep(i,200005) {
    sort(rall(t[i]));
    if (t[i].size()) t[i][0] += x;
    rep(j, t[i].size()) ord.pb(t[i][j]);
  }
  sort(rall(ord));
  vector<ll> s(n+1);
  rep(i,n) s[i+1] = s[i] + ord[i];

  int k;
  cin >> k;
  ll ans = 0;
  rep(i,k) {
    int c;
    cin >> c;
    ans += s[c];
  }
  cout << ans << endl;
  return 0;
}