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, p[200200], canget[200200];
pair<int, int> c[200200];
bool check(long long v) {
  long long tot = 0;
  for (int i = (0); i < (K + 1); i++) {
    long long l = (i == K ? S : p[i]) - (i == 0 ? 0 : p[i - 1]);
    if (v - l < 0) return 0;
    tot += 2 * l - min(l, v - l);
  }
  return tot <= (long long)T;
}
int main() {
  scanf("%d %d %d %d", &N, &K, &S, &T);
  for (int i = (0); i < (N); i++) scanf("%d %d", &c[i].first, &c[i].second);
  sort(c, c + N);
  for (int i = (0); i < (K); i++) {
    scanf("%d", &p[i]);
  }
  sort(p, p + K);
  long long lo = 0, hi = 1e9, mid, ans = -1;
  while (lo <= hi) {
    mid = (lo + hi) / 2;
    if (check(mid))
      ans = mid, hi = mid - 1;
    else
      lo = mid + 1;
  }
  if (ans == -1) return puts("-1"), 0;
  for (int i = (0); i < (N); i++)
    if (c[i].second >= int(ans)) return printf("%d\n", c[i].first), 0;
  puts("-1");
  return 0;
}
