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;
long long n, k, s, t, g[2 * 100005], l, r, mid, ans = 1e9 + 7;
pair<long long, long long> c[2 * 100005];
bool ck(long long x) {
  unsigned long long str = 1, tim = 0;
  for (int i = 0; i < k + 1; i++) {
    if (x < (g[i] - str) + 1 || tim > t)
      return false;
    else {
      long long q = (g[i] - str) + 1;
      tim += min(x - q, q) + ((q - min(x - q, q)) * (long long)2);
      str = g[i] + 1;
    }
  }
  if (tim <= t)
    return true;
  else
    return false;
}
int main() {
  ios_base::sync_with_stdio(false);
  cin >> n >> k >> s >> t;
  for (int i = 0; i < n; i++) cin >> c[i].second >> c[i].first;
  for (int i = 0; i < k; i++) cin >> g[i];
  sort(g, g + k);
  g[k] = s;
  l = 1, r = 1e9 + 3;
  while (l < r) {
    mid = (l + r) / 2;
    if (ck(mid) == false)
      l = mid + 1;
    else
      r = mid;
  }
  for (int i = 0; i < n; i++) {
    if (c[i].first >= l && ans > c[i].second) ans = c[i].second;
  }
  if (ans != 1e9 + 7)
    cout << ans;
  else
    cout << -1;
}
