#include <bits/stdc++.h>
using namespace std;
const bool print = false;
const int MAXN = 200111;
int n, k, s, t;
vector<pair<int, int> > cars;
vector<int> stations;
int chk(int tank) {
  int pop = 0;
  int ans = 0;
  if (print) printf("CHK %d::", tank);
  for (auto it : stations) {
    int odl = it - pop;
    int time = 2 * odl;
    int left = tank - odl;
    if (print) printf("%d %d ", odl, left);
    if (left < 0) return t + 69;
    time -= left;
    if (time < odl) time = odl;
    if (print) printf("%d;; ", time);
    ans += time;
    pop = it;
  }
  if (print) printf("%d\n", ans);
  return ans;
}
int main() {
  scanf("%d%d%d%d", &n, &k, &s, &t);
  for (int i = (1); i <= (n); i++) {
    int c, v;
    scanf("%d%d", &c, &v);
    cars.emplace_back(c, v);
  }
  for (int i = (1); i <= (k); i++) {
    int a;
    scanf("%d", &a);
    stations.push_back(a);
  }
  stations.push_back(s);
  sort((cars).begin(), (cars).end());
  sort((stations).begin(), (stations).end());
  int pop = 0;
  for (auto& it : cars) {
    if (pop > it.second) it.second = pop;
    pop = it.second;
  }
  cars.emplace_back(-1, (int)1e9);
  int lw = 1, pw = n + 1;
  while (lw < pw) {
    int sr = (lw + pw) / 2;
    int time69 = chk(cars[sr - 1].second);
    if (time69 <= t)
      pw = sr;
    else
      lw = sr + 1;
  }
  printf("%d\n", cars[lw - 1].first);
}
