#include<bits/stdc++.h>
using namespace std;
using ll=long long;
#define rep(i,n) for(ll i=0;i<n;i++)
#define all(A) A.begin(),A.end()

int main(){
    ll N,M,X;
    cin>>N>>M>>X;
    vector<vector<ll>> A(M);
    rep(i,N){
        ll a,b;
        cin>>a>>b;
        A[b-1].push_back(a);
    }
    vector<ll> P;
    rep(i,M){
        if(ll(A[i].size())==0)continue;
        sort(all(A[i]));
        reverse(all(A[i]));
        ll cnt=1;
        for(auto a:A[i]){
            P.push_back(a+X*cnt);
            cnt=0;
        }
    }
    
    sort(all(P));
    reverse(all(P));
    vector<ll> PS(N+1,0);
    rep(i,N)PS[i+1]+=PS[i]+P[i];
    
    ll an=0;
    ll K;
    cin>>K;
    rep(i,K){
        ll c;
        cin>>c;
        an+=PS[c];
    }
    cout<<an<<endl;

}