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, x, jum, a[200005], b[200005], g[200005], jar[200005],
    dp[200005], ans(1e18);
int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  cin >> n >> k >> s >> t;
  for (int i = 1; i <= n; i++) {
    cin >> a[i] >> b[i];
  }
  for (int i = 1; i <= k; i++) {
    cin >> g[i];
  }
  sort(g + 1, g + k + 1);
  for (int i = 1; i <= k; i++) {
    jar[i] = g[i] - g[i - 1];
  }
  jar[k + 1] = s - g[k];
  k++;
  sort(jar + 1, jar + k + 1);
  for (int i = 1; i <= k; i++) {
    dp[i] = dp[i - 1] + jar[i];
  }
  for (int i = 1; i <= n; i++) {
    if (jar[k] > b[i]) {
      continue;
    } else {
      x = upper_bound(dp + 1, dp + k + 1, b[i]) - dp - 1;
      if (dp[x] + (dp[k] - dp[x]) * 3 - b[i] * (k - x) <= t) {
        ans = min(ans, a[i]);
      }
    }
  }
  if (ans == 1e18) {
    cout << -1 << '\n';
  } else {
    cout << ans << '\n';
  }
  return 0;
}
