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;
using ull = unsigned long long;
int main() {
  cin.tie(nullptr);
  ios::sync_with_stdio(false);
  int n, k;
  long long int s, t;
  cin >> n >> k >> s >> t;
  vector<int> c(n), v(n);
  for (int i = 0; i < n; i++) {
    cin >> c[i] >> v[i];
  }
  vector<long long int> d(k);
  for (int i = 0; i < k; i++) {
    cin >> d[i];
  }
  d.push_back(0);
  sort(d.begin(), d.end());
  d.push_back(s);
  int ans = 2e9;
  int l = 0, r = 2e9 + 5;
  while (r - l > 1) {
    long long int mid = (l + r) / 2;
    bool ok = 1;
    long long int ti = 0;
    for (int i = 1; i < (int)d.size(); i++) {
      long long int di = d[i] - d[i - 1];
      if (di * 2 <= mid) {
        ti += di;
      } else if (di > mid) {
        ok = 0;
      } else {
        ti += (mid - di) + 2 * (di - (mid - di));
      }
    }
    if (ti > t) ok = 0;
    if (ok) {
      r = mid;
    } else {
      l = mid;
    }
  }
  for (int i = 0; i < n; i++) {
    if (r <= v[i]) {
      ans = min(ans, c[i]);
    }
  }
  if (ans == 2e9) {
    printf("-1\n");
  } else {
    printf("%d\n", ans);
  }
}
