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 compareup(const void *a, const void *b) { return (*(int *)a > *(int *)b); }
int comparedown(const void *a, const void *b) {
  return (*(int *)a < *(int *)b);
}
bool chek(int b, vector<int> &z, int t) {
  int to = 0;
  for (int i = 0; i < z.size() - 1; i++) {
    double r = z[i + 1] - z[i];
    if (r > b) return false;
    double maxus = b / 2;
    if (maxus > r) {
      to += r;
      continue;
    }
    double slow = (r - maxus) * 2;
    double fast = r - slow;
    to += fast + slow * 2;
  }
  if (to <= t) return true;
  return false;
}
int main() {
  ios::sync_with_stdio(false);
  int n, k, s, t, ansi = -1, min = -1;
  long long int to;
  bool pr;
  cin >> n >> k >> s >> t;
  vector<pair<int, int>> c(n);
  vector<int> z(k);
  for (int i = 0; i < n; i++) cin >> c[i].second >> c[i].first;
  for (int i = 0; i < k; i++) cin >> z[i];
  z.push_back(0);
  z.push_back(s);
  sort(z.begin(), z.end());
  sort(c.begin(), c.end());
  int l = 0, r = n;
  while (l != r) {
    int m = (l + r) / 2;
    pr = chek(c[m].first, z, t);
    if (pr) {
      r = m;
      if (ansi > c[m].second || ansi == -1) ansi = c[m].second;
    } else {
      l = m + 1;
    }
  }
  cout << ansi;
  return 0;
}
