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

int main(){
    cin.tie(0);
    ios::sync_with_stdio(0);
    
    ll N,M,X; cin >> N >> M >> X;
    vector<ll> A(N), B(N), C(N);
    rep(i,N) {
        cin >> A[i] >> B[i], B[i]--;
        C[i] = A[i] + X;
    }
    vector<int> used(N, 0);
    vector<vector<int>> id(M);
    rep(i,N) id[B[i]].push_back(i);

    set<pair<ll,int>> st;
    rep(i,N) st.insert({C[i], i});
    vector<ll> D;
    rep(_,N) {
        auto it = st.end(); it--;
        auto [c, i] = *it;
        D.push_back(c);
        st.erase({c, i});
        if(!used[i]) {
            for(int x : id[B[i]]) if(st.count({C[x], x})) {
                st.erase({C[x], x});
                C[x] -= X;
                used[x] = 1;
                st.insert({C[x], x});
            }
        }
    }

    vector<ll> sumD(N + 1, 0);
    rep(i,N) sumD[i + 1] += sumD[i] + D[i];
    ll ans = 0;
    int K; cin >> K;
    rep(i,K) {
        int c; cin >> c;
        ans += sumD[c];
    }
    cout << ans << endl;
}