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;
pair<int, int> a[200005];
int g[200005];
vector<pair<int, int> > v;
bool check(int j) {
  int last = 0;
  long long tot = 0;
  g[k] = s;
  for (int i = 0; i <= k; i++) {
    int cur = g[i];
    int l = 0, h = cur - last, mid, ans = -1;
    while (l <= h) {
      mid = (l + h) >> 1;
      int rem = cur - mid - last;
      if (mid * 2 + rem <= v[j].first) {
        l = mid + 1;
        ans = mid;
      } else
        h = mid - 1;
    }
    if (ans == -1) return 0;
    int rem = cur - ans - last;
    tot += ans + (rem * 2);
    if (tot > t) return 0;
    last = cur;
  }
  return 1;
}
int main() {
  scanf("%d%d%d%d", &n, &k, &s, &t);
  for (int i = 0; i < n; i++) {
    scanf("%d%d", &a[i].second, &a[i].first);
  }
  for (int i = 0; i < k; i++) {
    scanf("%d", &g[i]);
  }
  sort(a, a + n);
  for (int i = 0; i < n; i++) {
    while (v.empty() == false && v[v.size() - 1].second > a[i].second) {
      v.pop_back();
    }
    v.push_back(a[i]);
  }
  sort(g, g + k);
  int l = 0, h = v.size() - 1, mid, ans = -1;
  while (l <= h) {
    mid = (l + h) >> 1;
    if (check(mid)) {
      ans = mid;
      h = mid - 1;
    } else {
      l = mid + 1;
    }
  }
  cout << v[ans].second << "\n";
  return 0;
}
