#include <bits/stdc++.h>
#include <cstdlib>
#include <cmath>
#include <algorithm>
using namespace std;
using ll = long long;
using P = pair<ll,ll>;
using Graph= vector<vector<ll>>;
struct edge{ll to ; ll cost ;} ;
using graph =vector<vector<edge>> ;
#define rep(i,n) for (ll i=0; i < (n); ++i)
#define rep2(i,n,m) for(ll i=n;i<=m;i++)
#define rep3(i,n,m) for(ll i=n;i>=m;i--)
#define pb push_back
#define eb emplace_back
#define ppb pop_back
#define mpa make_pair
#define fi first
#define se second 
#define set20 cout<<fixed<<setprecision(20) ;
const ll INF=1e18 ;
inline void chmax(ll& a,ll b){a=max(a,b);}
inline void chmin(ll& a,ll b){a=min(a,b);}
double pi=acos(-1) ;
ll gcd(ll a, ll b) { return b?gcd(b,a%b):a;}
ll lcm(ll a, ll b) { return a/gcd(a,b)*b;}



int main(){
  ios::sync_with_stdio(false) ;
  cin.tie(nullptr) ;
  
 ll n,m,x ; cin>>n>>m>>x ;
 Graph g(m) ;
 rep(i,n){
   ll z,y ; cin>>z>>y ;
   g[y-1].pb(z) ;
 }
 vector<ll> all ;
 rep(i,m){
   if(!g[i].size()) continue ;
   sort(g[i].rbegin(),g[i].rend()) ;
   g[i][0]+=x ;
   for(auto u:g[i]) all.pb(u) ;
 }
 
 sort(all.rbegin(),all.rend()) ;
 
 vector<ll> rui(n+1) ;
 rui[0]=0 ;
 rep(i,n) rui[i+1]=rui[i]+all[i] ;
 ll ans=0ll ;
 ll k ; cin>>k ;
 rep(i,k){ll t ; cin>>t ;ans+=rui[t] ;}
 cout<<ans<<endl ;

  return  0 ; 
}