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;
int n, k, s, t;
int g[200005], c[200005], v[200005], l[200005];
int suml[200005];
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(nullptr);
  cout.tie(nullptr);
  cin >> n >> k >> s >> t;
  for (int i = 1; i <= n; i++) {
    cin >> c[i] >> v[i];
  }
  for (int i = 1; i <= k; i++) {
    cin >> g[i];
  }
  k++;
  sort(g + 1, g + k);
  g[k] = s;
  for (int i = 1; i <= k; i++) {
    l[i] = g[i] - g[i - 1];
  }
  sort(l + 1, l + k + 1);
  for (int i = 1; i <= k; i++) {
    suml[i] = suml[i - 1] + l[i];
  }
  int mc = 1999999999;
  for (int i = 1; i <= n; i++) {
    int c = ::c[i];
    int v = ::v[i];
    if (v < l[k]) {
      continue;
    }
    int split = upper_bound(l + 1, l + k + 1, v / 2) - l;
    int t_fast = suml[split - 1];
    long long t_eco =
        3ll * (suml[k] - suml[split - 1]) - v * 1ll * (k - split + 1);
    if (t_fast + t_eco <= t) {
      mc = min(mc, c);
    }
  }
  if (mc == 1999999999) {
    mc = -1;
  }
  cout << mc;
}
