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() {
  int n, k, s, t;
  cin >> n >> k >> s >> t;
  vector<pair<int, int> > c(n);
  vector<int> g(k);
  for (int i = 0; i < n; i++) cin >> c[i].first >> c[i].second;
  for (int i = 0; i < k; i++) cin >> g[i];
  sort(c.begin(), c.end(),
       [](const pair<int, int> &a, const pair<int, int> &b) {
         if (a.second != b.second) return a.second < b.second;
         return a.first < b.first;
       });
  g.push_back(s);
  k++;
  sort(g.begin(), g.end());
  auto can = [&](int fuel) {
    int lst = 0;
    int total_time = 0;
    for (int i = 0; i < k; i++) {
      int cur_dist = g[i] - lst;
      lst = g[i];
      if (cur_dist > fuel) return false;
      if (fuel > 2 * cur_dist)
        total_time += cur_dist;
      else
        total_time += 3 * cur_dist - fuel;
      if (total_time > t) return false;
    }
    return true;
  };
  int low = 0;
  int high = n - 1;
  int mid = 0;
  int valid = -1;
  while (low <= high) {
    mid = (low + high) / 2;
    if (can(c[mid].second)) {
      valid = mid;
      high = mid - 1;
    } else
      low = mid + 1;
  }
  if (valid != -1) {
    int ans = c[valid].first;
    for (int i = valid + 1; i < n; i++)
      if (ans > c[valid].first) ans = c[valid].first;
    cout << ans;
  } else
    cout << "-1";
  return 0;
}
