1 1 2 2
1000000000 1000000000
1
 1 1 1000000000 1000000000
100 1000000000
1
 1 1 10 18
5 6
5
 2 1 1000000000 2000000000
111 999999999
101 999999998
1
 4 13 400 600
13 30
1 19
1 160
1 113
58 73 15 319 194 362 128 157 336 162 77 90 96
 1 15 100 200
283 8
30 58 16 45 80 82 55 95 24 23 86 28 51 47 20
 3 2 300 400
24 68
13 65
15 113
127 177
 1 1 2 1
1 10
1
 4 2 7 15
10 9
4 4
9 3
4 10
1 6
 2 1 1000000000 2000000000
111 1000000000
101 1000000000
5
 2 1 1000000000 2000000000
111 999999998
101 999999998
1
 1 1 1000000000 1000000000
1 1000000000
1

1000000000
 -1
 5
 111
 1
 -1
 -1
 -1
 4
 101
 -1
 -1

#include <bits/stdc++.h>
using namespace std;
int main() {
  long long n, k, s, t;
  cin >> n >> k >> s >> t;
  vector<pair<long long, long long>> car;
  for (long long i = 0; i < n; ++i) {
    long long a, b;
    cin >> a >> b;
    car.push_back(make_pair(a, b));
  }
  vector<long long> station;
  long long wow = 0;
  for (long long i = 0; i < k; ++i) {
    long long tmp;
    cin >> tmp;
    station.push_back(tmp + wow);
    wow += tmp;
  }
  station.push_back(s);
  k++;
  sort(car.begin(), car.end());
  long long minimum_required = station[0];
  for (int i = 1; i < k; ++i) {
    minimum_required = max(minimum_required, station[i] - station[i - 1]);
  }
  long long fast = 0;
  vector<int> can_doit;
  station.insert(station.begin(), 0);
  k++;
  for (int i = 1; i < k; ++i) {
    int wow = station[i] - station[i - 1];
    if (2 * wow <= minimum_required) {
      fast += wow;
    } else {
      fast += 2 * (2 * wow - minimum_required) +
              (wow - (2 * wow - minimum_required));
      can_doit.push_back(2 * wow - minimum_required);
    }
  }
  int need_nenpi = 0;
  sort(can_doit.begin(), can_doit.end());
  t -= fast;
  if (t >= 0) {
    need_nenpi = minimum_required;
  } else {
    int speed = 0;
    int cost = can_doit.size();
    for (int i = 0; i < can_doit.size(); ++i) {
      int gogo = (can_doit[i] - speed) * cost;
      if (t + gogo >= 0) {
        t *= -1;
        speed += t / cost;
        if (t % cost != 0) {
          speed++;
        }
        t = 1;
        need_nenpi = speed + minimum_required;
      } else {
        t += gogo;
        cost--;
        speed = can_doit[i];
      }
    }
  ok:;
  }
  if (t < 0) {
    cout << "-1" << endl;
    return 0;
  }
  for (int i = 0; i < car.size(); ++i) {
    if (need_nenpi <= car[i].second) {
      cout << car[i].first << endl;
      return 0;
    }
  }
  cout << "-1" << endl;
  return 0;
}
