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, l, r, md, b;
pair<long long, long long> p[200005];
vector<long long> a;
bool check(long long fuel) {
  long long sum = 0, x, dist;
  for (int i = 1; i < a.size(); i++) {
    dist = a[i] - a[i - 1];
    if (dist > fuel) return 0;
    x = min(fuel - dist, dist);
    sum += 2 * dist - x;
  }
  if (sum <= t) return 1;
  return 0;
}
int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  cin >> n >> k >> s >> t;
  for (int i = 0; i < n; i++) cin >> p[i].first >> p[i].second;
  sort(p, p + n);
  for (int i = 1; i < n; i++) p[i].second = max(p[i].second, p[i - 1].second);
  for (int i = 0; i < k; i++) {
    cin >> b;
    a.push_back(b);
  }
  a.push_back(0);
  a.push_back(s);
  sort(a.begin(), a.end());
  l = 0, r = n;
  while (l < r) {
    md = (l + r) / 2;
    if (check(p[md].second) == 1)
      r = md;
    else
      l = md + 1;
  }
  if (l == n)
    cout << -1;
  else
    cout << p[l].first;
}
