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> > cars(n);
  for (int i = 0; i < n; i++) cin >> cars[i].second >> cars[i].first;
  vector<int> arr(k + 2);
  arr[0] = 0;
  arr[1] = s;
  for (int i = 0; i < k; i++) cin >> arr[i + 2];
  sort(arr.begin(), arr.end());
  sort(cars.begin(), cars.end());
  int lo = 0, hi = n;
  int ans = -1;
  while (lo <= hi) {
    int mid2 = (lo + hi) / 2;
    int mid = cars[mid2].first;
    int takes = 0;
    for (int i = 0; i < arr.size() - 1; i++) {
      if (takes > t) break;
      long long dist = arr[i + 1] - arr[i];
      if (dist > mid) {
        takes = t + 1;
        break;
      } else {
        int diff = mid - dist;
        if (diff >= dist)
          takes += dist;
        else
          takes += diff + (dist - diff) * 2;
      }
    }
    if (takes <= t) {
      hi = mid2 - 1;
      ans = ans == -1 ? cars[mid2].second : min(cars[mid2].second, ans);
    } else
      lo = mid2 + 1;
  }
  cout << ans << endl;
  return 0;
}
