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;
string world[8] = {"U", "D", "R", "L", "UL", "UR", "DR", "DL"};
const int rx[8] = {-1, 1, 0, 0, -1, -1, 1, 1};
const int ry[8] = {0, 0, 1, -1, -1, 1, 1, -1};
const long long mod = 1000000007;
int main() {
  int n, k, s, t;
  cin >> n >> k >> s >> t;
  pair<int, int> a[n];
  for (int i = 0; i < n; i++) {
    scanf("%d %d", &a[i].second, &a[i].first);
  }
  int g[k + 1];
  for (int i = 0; i < k; i++) {
    scanf("%d", &g[i]);
  }
  g[k] = s;
  k++;
  sort(g, g + k);
  sort(a, a + n);
  int ans = 1e9;
  int res = 1e9;
  int l = 0, r = n - 1;
  while (l <= r) {
    int m = (l + r) / 2;
    int mid = a[m].first;
    bool f = true;
    int L = 0;
    int t1 = 0;
    for (int i = 0; i < k; i++) {
      int R = g[i];
      int len = R - L;
      if (len > mid) {
        f = false;
        break;
      }
      int x = (mid - len);
      if (x >= len) x = len;
      t1 += x;
      t1 += (len - x) * 2;
      L = g[i];
    }
    if (t1 > t) f = false;
    if (f) {
      res = m;
      r = m - 1;
    } else {
      l = m + 1;
    }
  }
  if (res == 1e9) {
    cout << -1;
    return 0;
  }
  ans = a[res].second;
  for (int i = 0; i < n; i++) {
    if (a[i].first >= a[res].first) ans = min(ans, a[i].second);
  }
  cout << ans << endl;
  return 0;
}
