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<int, int> all[200005];
int l[200005];
int n, k;
long long calc(long long v) {
  long long res = 0;
  for (int i = 0; i < k; i++)
    if (l[i] > v)
      return 1ll << 62;
    else if (2 * l[i] < v)
      res += l[i];
    else
      res += 3 * l[i] - v;
  return res;
}
bool can(long long test, long long tim) { return calc(test) <= tim; }
int solve(int t) {
  long long lo = 0, hi = 1ll << 60;
  while (lo + 1 < hi) {
    long long mid = (lo + hi) >> 1;
    if (can(mid, t))
      hi = mid;
    else
      lo = mid;
  }
  int bst = -1;
  for (int i = 0; i < n; i++)
    if (all[i].second >= hi) {
      if (bst == -1) bst = i;
      if (all[i].first < all[bst].first) bst = i;
    }
  return all[bst].first;
}
int main() {
  int s, t;
  scanf("%d%d%d%d", &n, &k, &s, &t);
  for (int i = 0; i < n; i++) scanf("%d%d", &all[i].first, &all[i].second);
  for (int i = 0; i < k; i++) scanf("%d", l + i);
  l[k] = s;
  k++;
  sort(l, l + k);
  for (int i = k - 1; i > 0; i--) l[i] -= l[i - 1];
  printf("%d\n", solve(t));
  return 0;
}
