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 n, k, s, t, c[200005], v[200005], g[200005];
int32_t main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  cin >> n >> k >> s >> t;
  for (long long i = 0; i < n; i++) cin >> c[i] >> v[i];
  for (long long i = 0; i < k; i++) cin >> g[i];
  sort(g, g + k);
  g[k] = s;
  long long L = -1;
  long long R = 2e9 + 7;
  while (R - L > 1) {
    long long M = (L + R) / 2;
    long long T = 0;
    for (long long i = -1; i < k; i++) {
      long long x;
      if (i != -1)
        x = g[i + 1] - g[i];
      else
        x = g[0];
      long long y = max(0ll, 2 * x - M);
      if (y > x)
        T = 2e9 + 7;
      else
        T += x + y;
    }
    if (T <= t)
      R = M;
    else
      L = M;
  }
  long long Min = 2e9 + 7;
  for (long long i = 0; i < n; i++) {
    if (v[i] >= R) Min = min(Min, c[i]);
  }
  if (Min == 2e9 + 7)
    cout << -1;
  else
    cout << Min;
}
