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 n, k, s, t, b[(long long)(5 + 2e5)];
pair<int, int> a[(long long)(5 + 2e5)];
bool CMP(pair<int, int> a, pair<int, int> b) { return a.second < b.second; }
bool Try(int C) {
  long long T = t, d;
  for (int i = 0; i < k; i++)
    if (C < (d = b[i + 1] - b[i]))
      return 0;
    else if (C >= 2 * d)
      T -= d;
    else
      T -= 2 * d - (C - d);
  return T >= 0;
}
int solve() {
  int l = 0, r = n - 1, mid;
  while (l + 1 < r) {
    mid = l + r >> 1;
    if (Try(a[mid].second))
      r = mid;
    else
      l = mid + 1;
  }
  if (Try(a[l].second)) return a[l].second;
  return a[r].second;
}
int main() {
  cin >> n >> k >> s >> t;
  for (int i = 0; i < n; i++) scanf("%d%d", &a[i].first, &a[i].second);
  for (int i = 0; i < k; i++) scanf("%d", &b[i]);
  b[k] = s;
  sort(a, a + n, CMP);
  k++;
  sort(b, b + k + 1);
  a[n++] = {1 + 2e9, 1 + 2e9};
  int ans = solve();
  n--;
  sort(a, a + n);
  for (int i = 0; i < n; i++)
    if (a[i].second >= ans) {
      cout << a[i].first << endl;
      return 0;
    }
  cout << -1 << endl;
  return 0;
}
