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;
long long t;
vector<pair<int, int> > cv;
vector<long long> g, d;
long long fu(long long v, long long dd) {
  if (dd > v) return (long long)3e9;
  if (dd + dd <= v) return dd;
  return (v + v - 3ll * (v - dd));
}
bool ok(long long v) {
  long long sum = 0;
  for (int i = 0; i < d.size(); ++i) sum += fu(v, d[i]);
  return (sum <= t);
}
int main() {
  ios_base::sync_with_stdio(false);
  cin >> n >> k >> s >> t;
  cv.resize(n);
  for (int i = 0; i < n; ++i) cin >> cv[i].first >> cv[i].second;
  sort(cv.begin(), cv.end());
  g.resize(k);
  for (int i = 0; i < k; ++i) cin >> g[i];
  g.push_back(0);
  g.push_back(s);
  sort(g.begin(), g.end());
  for (int i = 1; i < g.size(); ++i) d.push_back(g[i] - g[i - 1]);
  int l = 0;
  int r = 1000000000;
  if (!ok(r)) {
    cout << -1 << endl;
    return 0;
  }
  while (r - l > 1) {
    int mid = (r + l) / 2;
    (ok(mid) ? r : l) = mid;
  }
  int res = 2000000000;
  for (int i = 0; i < n; ++i) {
    if (cv[i].second >= r) res = min(res, cv[i].first);
  }
  if (res == 2000000000) res = -1;
  cout << res << endl;
  return 0;
}
