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;
vector<pair<int, int> > c(200005);
vector<int> z;
int main() {
  int n, k, s, t;
  cin >> n >> k >> s >> t;
  for (int i = 0; i < n; i++) {
    scanf("%d%d", &c[i].first, &c[i].second);
  }
  z.resize(k + 2);
  z[0] = 0;
  z[k + 1] = s;
  for (int i = 1; i <= k; i++) {
    int x;
    scanf("%d", &z[i]);
  }
  sort(z.begin(), z.end());
  int l = 1;
  int r = s;
  while (l < r - 1) {
    int m = (r + l) / 2;
    int ct = 0;
    for (int i = 0; i < z.size() - 1; i++) {
      int d = z[i + 1] - z[i];
      if (m < d) {
        ct += 2e9;
        break;
      } else {
        ct += d * 2 - min(d, m - d);
      }
    }
    if (ct > t) {
      l = m;
    } else
      r = m;
  }
  int m = l;
  int ct = 0;
  int ans = 0;
  for (int i = 0; i < z.size() - 1; i++) {
    int d = z[i + 1] - z[i];
    if (m < d) {
      ct += 2e9;
      break;
    } else {
      ct += d * 2 - min(d, m - d);
    }
  }
  if (ct <= t)
    ans = l;
  else
    ans = r;
  int mn = 1e9;
  for (int i = 0; i < c.size(); i++) {
    if (c[i].second >= ans) mn = min(mn, c[i].first);
  }
  if (mn == 1e9) {
    cout << -1;
  } else
    cout << mn;
  return 0;
}
