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 long long maxn = 1000 * 1000 * 1000 + 10;
const int mxn = 1000 * 1000;
int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  cout.tie(0);
  ;
  vector<pair<long long, long long> > c;
  long long n, k, s, t, g[mxn], sum[mxn], mx = 0, ans = maxn, tm;
  cin >> n >> k >> s >> t;
  for (int i = 0; i < n; i++) {
    long long a, b;
    cin >> a >> b;
    c.push_back(make_pair(a, b));
  }
  g[0] = 0;
  for (int i = 1; i <= k; i++) cin >> g[i];
  sort(g, g + k + 1);
  g[k + 1] = s;
  for (int i = 0; i <= k; i++) {
    g[i] = g[i + 1] - g[i];
    mx = max(g[i], mx);
  }
  sum[0] = g[0];
  for (int i = 1; i < k + 2; i++) sum[i] = sum[i - 1] + g[i];
  for (int i = 0; i < n; i++) {
    if (c[i].second < mx) continue;
    long long up = upper_bound(g, g + k + 1, c[i].second / 2) - g - 1;
    if (up == -1)
      tm = 3 * s - (c[i].second * (k + 1));
    else
      tm = sum[up] + (3 * (s - sum[up])) - (c[i].second * (k - up));
    if (tm <= t) ans = min(ans, c[i].first);
    if (c[i].first == 1216848)
      cout << up << ' ' << sum[up] << ' ' << c[i].second << endl;
    if (c[i].first == 84274778)
      cout << up << ' ' << sum[up] << ' ' << c[i].second << endl;
  }
  if (ans < maxn)
    cout << ans << endl;
  else
    cout << -1;
  return 0;
}
