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<long long, long long> a[200001];
long long x[200001];
int main() {
  long long n, k, s, t;
  scanf("%I64d%I64d%(i6d%I64d", &n, &k, &s, &t);
  for (int i = 0; i < n; i++) {
    scanf("%I64d%I64d", &a[i].second, &a[i].first);
  }
  sort(a, a + n);
  for (int i = 0; i < k; i++) scanf("%I64d", &x[i]);
  x[k] = s;
  k++;
  sort(x, x + k);
  if (t < s) {
    cout << -1;
    return 0;
  }
  long long ost = t - s;
  long long now = 0;
  bool fl = 0;
  for (int i = 0; i < k; i++) {
    if (x[i] - now > a[n - 1].first) {
      fl = 1;
      break;
    }
    if (2 * (x[i] - now) <= a[n - 1].first) {
      now = x[i];
      continue;
    }
    ost -= 2 * (x[i] - now) - a[n - 1].first;
    if (ost < 0) break;
    now = x[i];
  }
  if (fl || ost < 0) {
    cout << -1;
    return 0;
  }
  int l = -1, r = n - 1;
  while (r - l > 1) {
    int m = (l + r) / 2;
    ost = t - s;
    now = 0;
    fl = 0;
    for (int i = 0; i < k; i++) {
      if (x[i] - now > a[m].first) {
        fl = 1;
        break;
      }
      if (2 * (x[i] - now) <= a[m].first) {
        now = x[i];
        continue;
      }
      ost -= 2 * (x[i] - now) - a[m].first;
      if (ost < 0) break;
      now = x[i];
    }
    if (ost < 0 || fl)
      l = m;
    else
      r = m;
  }
  long long ans = a[r].second;
  for (int i = r; i < n; i++) ans = min(ans, a[i].second);
  cout << ans << '\n';
  return 0;
}
