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 int64_t N = 1e6, M = 1e10;
int64_t c[N], v[N], g[N], d[N];
int main() {
  ios_base::sync_with_stdio(0), cin.tie(0), cout.tie(0);
  int64_t n, k, s, t, h, l, m, r = M;
  cin >> n >> k >> s >> t;
  for (int64_t i = 0; i < n; i++) cin >> c[i] >> v[i];
  for (int64_t i = 1; i <= k; i++) cin >> g[i];
  g[k + 1] = s;
  sort(g, g + k + 2);
  for (int64_t i = 1; i < k + 2; i++) d[i] = g[i] - g[i - 1];
  sort(d + 1, d + k + 2);
  h = 2 * (l = d[k + 1]);
  while (l < h) {
    m = (l + h) / 2, s = 0;
    for (int64_t i = 1; i < k + 2; i++) s += 3 * d[i] - min(m, 2 * d[i]);
    if (s > t)
      l = m + 1;
    else
      h = m;
  }
  for (int64_t i = 0; i < n; i++)
    if (v[i] >= l) r = min(r, c[i]);
  cout << (r == M ? -1 : r);
}
