#include <bits/stdc++.h>
using namespace std;
long long int mod = 1000000007;
long long n, k, s, t;
pair<long long, long long> c[200003];
long long x[200004];
int check(long long i) {
  long h = c[i].first;
  long long to = 0;
  for (long j = 1; j <= k; j++) {
    long long f = x[j] - x[j - 1];
    if (f > h) return 0;
    long long p = h - f;
    if (p > f) p = f;
    to = to + p + (f - p) * 2LL;
  }
  if (to <= t) return 1;
  return 0;
}
int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  cout.tie(0);
  cin >> n >> k >> s >> t;
  for (long i = 1; i <= n; i++) {
    cin >> c[i].second >> c[i].first;
  }
  for (long i = 1; i <= k; i++) cin >> x[i];
  sort(x + 1, x + k + 1);
  x[0] = 0;
  k++;
  x[k] = s;
  sort(c + 1, c + n + 1);
  long l = 0;
  long r = n;
  if (check(n) == 0) {
    cout << "-1" << endl;
    return 0;
  }
  while (r - l > 1) {
    long mid = (l + r) / 2;
    if (check(mid))
      r = mid;
    else
      l = mid;
  }
  long mm = c[r].second;
  for (long i = 1; i <= n; i++) {
    if (c[i].first >= c[r].first && c[i].second < mm) mm = c[i].second;
  }
  cout << mm << endl;
}
