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;
set<int> st;
vector<int> v1;
multimap<int, int> mp;
multimap<int, int>::iterator it;
int main() {
  int n, k, s, t, c, v, f = 0;
  cin >> n >> k >> s >> t;
  for (int i = 0; i < n; i++) {
    cin >> c >> v;
    mp.insert(make_pair(c, v));
  }
  for (int i = 0; i < k; i++) {
    cin >> c;
    v1.push_back(c);
  }
  sort(v1.begin(), v1.end());
  for (it = mp.begin(); it != mp.end(); it++) {
    c = it->first;
    v = it->second;
    if (v / 2 >= v1[0]) {
      t -= v1[0];
      s -= v1[0];
    } else if (v >= v1[0]) {
      t -= (2 * v1[0]);
      s -= v1[0];
    } else
      continue;
    if (v / 2 >= s && t - s >= 0)
      st.insert(c);
    else if (v >= s && t - (2 * s) >= 0)
      st.insert(c);
  }
  if (st.empty())
    cout << -1 << endl;
  else
    cout << *st.begin() << endl;
  return 0;
}
