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 b[200 * 1000 + 10], c[200 * 1000 + 10], v[200 * 1000 + 10];
int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  long long n, k, s, t;
  cin >> n >> k >> s >> t;
  for (long long i = 1; i <= n; i++) cin >> c[i] >> v[i];
  for (long long j = 1; j <= k; j++) cin >> b[j];
  sort(b + 1, b + k + 1);
  b[k + 1] = s;
  long long l = 0, r = 1e9;
  long long tc = 0;
  for (long long j = 1; j <= k + 1; j++) {
    if (b[j] - b[j - 1] > r) {
      cout << "-1\n";
      return 0;
    }
    tc += (b[j] - b[j - 1]) * 2 - min(r - (b[j] - b[j - 1]), b[j] - b[j - 1]);
  }
  if (tc > t) {
    cout << "-1";
    return 0;
  }
  while (r - l > 1) {
    long long m = (l + r) / 2;
    tc = 0;
    for (long long j = 1; j <= k + 1; j++) {
      if (b[j] - b[j - 1] > m) {
        l = m;
        goto m1;
      }
      tc += (b[j] - b[j - 1]) * 2 - min(m - (b[j] - b[j - 1]), b[j] - b[j - 1]);
    }
    if (tc <= t)
      r = m;
    else
      l = m;
  m1:;
  }
  long long ans = LLONG_MAX;
  for (long long i = 1; i <= n; i++) {
    if (v[i] >= r && c[i] < ans) ans = c[i];
  }
  if (ans == LLONG_MAX)
    cout << "-1";
  else
    cout << ans;
  return 0;
}
