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, gas[200005], mx, mn = -1, mncap = 2e9, idb, idf, idm, d;
pair<int, int> car[200005];
map<int, int> mmap;
map<int, int>::iterator it, it2;
long long ut;
int main() {
  scanf("%d %d %d %d", &n, &k, &s, &t);
  for (int i = 0; i < n; ++i) scanf("%d %d", &car[i].first, &car[i].second);
  for (int i = 1; i <= k; ++i) scanf("%d", &gas[i]);
  sort(car, car + n);
  sort(gas + 1, gas + k + 1);
  gas[k + 1] = s;
  idf = 1;
  idb = s;
  while (idf <= idb) {
    idm = (idf + idb) / 2;
    ut = 0;
    for (int i = 1; i <= k + 1; ++i) {
      d = gas[i] - gas[i - 1];
      if (idm < d) {
        ut = 2e9 + 1;
        break;
      }
      if (2 * d <= idm)
        ut += d;
      else
        ut += 3LL * d - idm;
    }
    if (ut <= t) {
      mncap = min(mncap, idm);
      idb = idm - 1;
    } else
      idf = idm + 1;
  }
  for (int i = 0; i < n; ++i)
    if (car[i].second >= mncap) {
      printf("%d\n", car[i].first);
      return 0;
    }
  printf("-1\n");
  return 0;
}
