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;
long long s, t, g[200007], c, v;
pair<long long, long long> car[200007];
int check(int x) {
  long long sum = 0, dis = 0, cur = 0, val = car[x].first;
  for (int i = 1; i <= k + 1; i++) {
    long long pl = g[i];
    if (i == 1)
      dis = pl - 0;
    else
      dis = pl - g[i - 1];
    if (dis > val) return 0;
    cur = dis * 2;
    if (cur <= val)
      sum += dis;
    else {
      sum += dis + (cur - val);
    }
  }
  if (sum <= t)
    return 1;
  else
    return 0;
}
int main() {
  ios_base::sync_with_stdio(0);
  cin >> n >> k >> s >> t;
  for (int i = 1; i <= n; i++) {
    cin >> c >> v;
    car[i] = make_pair(v, c);
  }
  for (int i = 1; i <= k; i++) {
    cin >> g[i];
  }
  sort(g + 1, g + 1 + k);
  g[k + 1] = s;
  sort(car + 1, car + 1 + n);
  int start = 1, en = n;
  int mid = (start + en) / 2;
  if (check(n) == 0) {
    cout << -1;
    return 0;
  }
  int cnp = 500;
  while (cnp--) {
    if (check(mid) == 1)
      en = mid;
    else
      start = mid + 1;
    mid = (start + en) / 2;
  }
  long long ans = 1e16;
  for (int i = mid; i <= n; i++) {
    ans = min(ans, car[i].second);
  }
  cout << ans;
}
