#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using V = vector<ll>;
using VV = vector<V>;
using VS = vector<string>;
using P = pair<ll,ll>;
using M = map<ll,ll>;
using Q = queue<ll>;
using PQ = priority_queue<ll>;
using PQG = priority_queue<ll,V,greater<ll>>;
using S = set<ll>;
const ll MOD = 1000000007;
const ll Mod = 998244353;
const ll INF = 1LL << 60;
#define rep(i,n) for(int i = 0; i < n; i++)
#define rep2(i,s,n) for(int i = s; i < n; i++)
#define rep3(i,s,n) for(int i = s; i <= n; i++)
#define all(x) (x).begin(),(x).end()
#define MP(a,b) make_pair(a,b)
#define fi first
#define se second
#define pb push_back
#define pf push_front
#define ppb pop_back
#define ppf pop_front
template<class T>bool chmin(T&a, const T&b){if(a>b){a=b;return 1;}return 0;}
template<class T>bool chmax(T&a, const T&b){if(a<b){a=b;return 1;}return 0;}
template<class T>void Vin(vector<T>&a){rep(i,(int)a.size())cin>>a[i];}
template<class T>void Vout(const vector<T>&a){rep(i,(int)a.size())cout<<a[i]<<endl;}
ll power(ll a,ll b,const ll&M){a%=M;ll res=1;while(b>0){if(b&1)res=res*a%M;a=a*a%M;b>>=1;}return res;}
const ll H[4] = {0,1,0,-1}, W[4] = {1,0,-1,0};

int main() {
  ll n, m, x;
  cin >> n >> m >> x;
  vector<P> pro(n);
  rep(i,n) {
    ll a, b;
    cin >> a >> b;
    pro.pb({a,b-1});
  }
  sort(all(pro));
  reverse(all(pro));
  vector<bool> genre(m);
  rep(i,n) if(!genre[pro[i].se]) {
    genre[pro[i].se] = 1;
    pro[i].fi += x;
  }
  sort(all(pro));
  reverse(all(pro));
  ll k, ans = 0;
  cin >> k;
  V cnt(n+1);
  rep(i,k) {
    ll c;
    cin >> c;
    cnt[c]++;
  }
  ll num = k;
  rep(i,n) {
    num -= cnt[i];
    if(num == 0) break;
    ans += pro[i].fi*num;
  }
  cout << ans << endl;
}