#include <bits/stdc++.h>
using namespace std;
using ll = long long;
const ll MOD = 1000000007;
using P = pair<ll,int>;
#define rep(i, n) for(int i = 0; i < n; i++)
#define all(x) (x).begin(),(x).end()

int main(){
    int n,m,x,k;
    cin >> n >> m >> x;
    vector<P> ab(n);
    rep(i,n) cin >> ab[i].first >> ab[i].second;
    sort(all(ab)); reverse(all(ab));
    priority_queue<ll> pq;
    set<int> se;
    rep(i,n){
        ll p = 0;
        if(!se.count(ab[i].second)) p += x;
        p += ab[i].first;
        pq.push(p);
        se.insert(ab[i].second);
    }
    vector<ll> pls(n+1);
    pls[0] = 0;
    ll tot = 0, ans = 0;
    rep(i,n){
        tot += pq.top();
        pq.pop();
        pls[i+1] = tot;
    }
    cin >> k;
    rep(i,k){
        int c;
        cin >> c;
        ans += pls[c];
    }
    cout << ans << endl;
    return 0;
}