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 n, k, s, t;
vector<pair<int, int> > v;
vector<int> g;
bool f(int u) {
  int p = 0;
  long long tx = 0;
  for (int i = 0; i <= k; i++) {
    int x = i < k ? g[i] : s;
    if (x - p > v[u].second) return false;
    int d = min(x - p, v[u].second - (x - p));
    tx += d + 2LL * (x - p - d);
    p = x;
  }
  return tx <= t;
}
int main(void) {
  ios::sync_with_stdio(false);
  cin >> n >> k >> s >> t;
  v.resize(n);
  g.resize(k);
  for (int(i) = (0); (i) < (n); ++(i)) cin >> v[i].first >> v[i].second;
  sort(v.begin(), v.end());
  for (int(i) = (0); (i) < (k); ++(i)) cin >> g[i];
  sort(g.begin(), g.end());
  for (int(i) = (1); (i) < (n); ++(i))
    v[i].second = max(v[i].second, v[i - 1].second);
  int lo = 0, hi = n - 1;
  while (lo != hi) {
    int mi = (lo + hi) / 2;
    if (f(mi))
      hi = mi;
    else
      lo = mi + 1;
  }
  if (lo == n)
    cout << "-1\n";
  else
    cout << v[lo].first << '\n';
  return 0;
}
