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;
signed main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  long long n, k, s, t;
  cin >> n >> k >> s >> t;
  vector<pair<long long, long long> > a(n);
  for (long long i = 0; i < n; i++) cin >> a[i].first >> a[i].second;
  sort((a).begin(), (a).end());
  vector<long long> b(k);
  for (long long i = 0; i < k; i++) cin >> b[i];
  b.push_back(0);
  b.push_back(s);
  sort((b).begin(), (b).end());
  vector<long long> pref(n + 1, 0);
  for (long long i = 0; i < n; i++) pref[i + 1] = max(pref[i], a[i].second);
  long long l = -1, r = n;
  while (l + 1 < r) {
    long long m = (l + r) / 2;
    long long ttime = 0, tmp = pref[m + 1];
    for (long long j = 1; j < b.size(); j++) {
      long long c = b[j] - b[j - 1];
      if (tmp < c) {
        ttime = 1e18;
        break;
      }
      long long z = min(c, tmp - c);
      ttime += z * 1 + (c - z) * 2;
    }
    if (ttime <= t)
      r = m;
    else
      l = m;
  }
  cout << (r == n ? -1 : a[r].first);
}
