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;
const int maxn = 2e5 + 10;
pair<int, int> a[maxn];
int b[maxn], ans = 2e9 + 10, st[maxn], n, k, s, t;
int f(int x) {
  int cap = a[x].first, tim = 0;
  for (int i = 0; i <= k; i++) {
    if (st[i] > cap) return 2e9 + 10;
    tim += max(3 * st[i] - cap, (st[i] + 1) / 2);
  }
  return tim;
}
int main() {
  ios_base::sync_with_stdio(false);
  cin >> n >> k >> s >> t;
  for (int i = 0; i < n; i++) cin >> a[i].second >> a[i].first;
  int pre = 0;
  for (int i = 0; i < k; i++) cin >> b[i];
  sort(b, b + k);
  for (int i = 0; i < k; i++) st[i] = b[i] - pre, pre = b[i];
  st[k] = s - pre;
  sort(a, a + n);
  int lo = -1, hi = n;
  while (hi - lo > 1) {
    int mid = (hi + lo) / 2;
    if (f(mid) < t)
      hi = mid;
    else
      lo = mid;
  }
  if (lo + 1 == n) return cout << -1, 0;
  for (int i = lo + 1; i < n; i++) ans = min(ans, a[i].second);
  cout << ans;
}
