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;
const int N = 200 * 1000 + 10;
long long n, k, s, t, a[N], b[N], p[N];
bool ok(long long x) {
  if (p[0] > x || s - p[k - 1] > x) return false;
  long long num = 0;
  num += min(p[0], x - p[0]);
  num += min(s - p[k - 1], x - (s - p[k - 1]));
  for (int i = 1; i <= k - 1; i++) {
    if (p[i] - p[i - 1] > x) return false;
    num += min(p[i] - p[i - 1], x - (p[i] - p[i - 1]));
  }
  if (2 * s - num <= t) return true;
  return false;
}
long long bs(long long s, long long e) {
  if (e - s < 2) return s;
  long long mid = (s + e) / 2;
  if (ok(mid - 1)) return bs(s, mid);
  return bs(mid, e);
}
int main() {
  ios_base::sync_with_stdio(false);
  cin >> n >> k >> s >> t;
  for (int i = 0; i <= n - 1; i++) cin >> a[i] >> b[i];
  for (int i = 0; i <= k - 1; i++) cin >> p[i];
  sort(p, p + k);
  long long v = bs(0, (1000 * 1000 * 1000) + 10);
  long long ind = -1;
  for (int i = 0; i <= n - 1; i++)
    if (b[i] >= v && (ind == -1 || a[ind] > a[i])) ind = i;
  if (ind == -1)
    cout << -1 << endl;
  else
    cout << a[ind] << endl;
  return 0;
}
