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;
bool if_match(int v, vector<int> &st, int t) {
  int time = 0;
  for (int i = 0; i < st.size() - 1; ++i) {
    int s = st[i + 1] - st[i];
    if (2 * s > v) return false;
    time += s;
  }
  if (t >= time)
    return true;
  else
    return false;
}
int main() {
  int n, k, s, t;
  cin >> n >> k >> s >> t;
  vector<int> answer, oil_st(k + 2);
  vector<pair<int, int> > car(n);
  for (int i = 0; i < n; ++i) cin >> car[i].second >> car[i].first;
  oil_st[0] = 0;
  for (int i = 1; i < k + 1; ++i) cin >> oil_st[i];
  oil_st[k + 1] = s;
  sort(car.begin(), car.end());
  int l = 0, r = n - 1;
  while (l < r) {
    int m = (l + r - 1) / 2 + 1;
    if (if_match(car[m].first, oil_st, t))
      l = m;
    else
      r = m - 1;
  }
  ++l;
  if ((l == n - 1) && (!if_match(car[l].first, oil_st, t))) {
    cout << -1;
    return 0;
  }
  answer.resize(n - l);
  int ind = 0;
  for (int i = l; i < n; ++i) {
    answer[ind] = car[i].second;
    ++ind;
  }
  sort(answer.begin(), answer.end());
  cout << answer[0];
  return 0;
}
