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 a[200010], c[200010], v[200010];
vector<pair<long long, long long> > ev;
long long int gets(int cap, int en) {
  int cur = 0;
  long long int ans = 0LL;
  for (int i = 1; i <= en; i++) {
    if (a[i] - cur > cap) return 1000000007;
    if (2 * (a[i] - cur) <= cap) {
      ans += a[i] - cur;
      cur = a[i];
      continue;
    } else {
      int d = a[i] - cur;
      ans += (2 * d - cap) * 2 + (d - (2 * d - cap));
      cur = a[i];
      continue;
    }
  }
  return ans;
}
long long int gets(long long int v) {
  if (ev[ev.size() - 1].first > v) return 1000000007;
  vector<pair<long long, long long> >::iterator it = --lower_bound(
      ev.begin(), ev.end(), make_pair(v / 2LL, 10000000000000000LL));
  pair<long long, long long> t = *it;
  int ind = it - ev.begin();
  long long int ret = t.second - 1LL * (ev.size() - ind - 1LL) * (v) +
                      3LL * (ev[ev.size() - 1].second - t.second);
  return ret;
}
int main() {
  int n, k, s, t;
  cin >> n >> k >> s >> t;
  for (int i = 1; i <= n; i++) {
    cin >> c[i] >> v[i];
  }
  for (int i = 1; i <= k; i++) cin >> a[i];
  sort(a + 1, a + k + 1);
  a[k + 1] = s;
  for (int i = 0; i <= k + 1; i++) {
    ev.push_back(make_pair(a[i] - a[i - 1], 0LL));
  }
  ev.push_back(make_pair(0LL, 0LL));
  sort(ev.begin(), ev.end());
  for (int i = 1; i < ev.size(); i++)
    ev[i].second = ev[i - 1].second + ev[i].first;
  int res = 1000000007;
  for (int i = 1; i <= n; i++) {
    if (gets(v[i]) <= t) res = min(res, c[i]);
  }
  if (res != 1000000007)
    cout << res << endl;
  else
    cout << -1 << endl;
  return 0;
}
