#include <bits/stdc++.h>
using namespace std;
int n, k, s, t;
vector<pair<int, int> > inf_car;
vector<int> fuel_stop;
bool f(int x) {
  unsigned long long ans = 0;
  for (int i = 0; i < k + 1; i++) {
    int len = fuel_stop[i + 1] - fuel_stop[i];
    if (x < len) {
      return 0;
    }
    if (x >= 2 * len) {
      ans += len;
      continue;
    }
    ans += 3 * len - x;
  }
  if (ans > t) {
    return 0;
  } else {
    return 1;
  }
}
int main() {
  ios_base::sync_with_stdio(false);
  cin >> n >> k >> s >> t;
  inf_car.resize(n);
  for (int i = 0; i < n; i++) {
    cin >> inf_car[i].first >> inf_car[i].second;
  }
  fuel_stop.resize(k + 2);
  for (int i = 1; i < k + 1; i++) {
    cin >> fuel_stop[i];
  }
  fuel_stop[k + 1] = s;
  sort(fuel_stop.begin(), fuel_stop.end());
  unsigned long long l = -1, r = 2 * 1e9 + 1;
  while (r - l > 1) {
    unsigned long long mid = (r + l) / 2;
    if (f(mid)) {
      r = mid;
    } else {
      l = mid;
    }
  }
  unsigned long long min_fuel;
  if (r == 2 * 1e9 + 1) {
    min_fuel = l;
  } else {
    min_fuel = r;
  }
  int ans = -1;
  for (auto c : inf_car) {
    if (c.second < min_fuel) {
      continue;
    }
    if (ans == -1) {
      ans = c.first;
      continue;
    }
    ans = min(ans, c.first);
  }
  cout << ans;
}
