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;
pair<int, int> A[200000];
int B[200000];
long long C[200002];
int main() {
  long long t;
  int n, k, s;
  cin >> n >> k >> s >> t;
  for (int i = 0; i < n; ++i) cin >> A[i].first >> A[i].second;
  for (int i = 0; i < k; ++i) cin >> B[i];
  sort(B, B + k);
  C[0] = B[0];
  for (int i = 1; i < k; ++i) C[i] = B[i] - B[i - 1];
  C[k] = s - B[k - 1];
  k += 1;
  sort(C, C + k);
  int lo = 0, hi = 1e9;
  while (lo < hi) {
    int mi = (lo + hi) >> 1;
    long long rx = 0;
    if (C[k - 1] > mi) {
      lo = mi + 1;
      continue;
    }
    for (int i = 0; i < k; ++i) rx += max(3 * C[i] - mi, C[i]);
    if (rx <= t)
      hi = mi;
    else
      lo = mi + 1;
  }
  int mx = 1e9 + 1;
  for (int i = 0; i < n; ++i)
    if (A[i].second >= lo) mx = min(mx, A[i].first);
  cout << (mx == 1e9 + 1 ? -1 : mx);
  return 0;
}
