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;
long long n, k, s, t, a[200005], b[200005], gas[200005], l = 1, r = 1e10, mid,
                                                         ans = 1e10;
int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  cin >> n >> k >> s >> t;
  for (long long i = 1; i <= n; i++) {
    cin >> a[i] >> b[i];
  }
  for (long long i = 1; i <= k; i++) {
    cin >> gas[i];
  }
  gas[k + 1] = s;
  sort(gas + 1, gas + k + 2);
  while (l < r) {
    mid = (l + r) / 2;
    long long time = 0;
    for (long long i = 1; i <= k + 1; i++) {
      if (gas[i] - gas[i - 1] > mid) {
        time += 1e10;
        break;
      }
      time += 2 * (gas[i] - gas[i - 1]) -
              min(gas[i] - gas[i - 1], mid - (gas[i] - gas[i - 1]));
    }
    if (time < t)
      r = mid - 1;
    else
      l = mid + 1;
  }
  for (long long i = 1; i <= n; i++) {
    if (b[i] >= r) ans = min(ans, a[i]);
  }
  cout << ans << '\n';
}
