#include <bits/stdc++.h>
using namespace std;
int g[200001];
int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  int n, k, t, s, el;
  cin >> n >> k >> s >> t;
  vector<pair<int, int>> v(n);
  for (int i = 0; i < n; i++) {
    cin >> v[i].first >> v[i].second;
  }
  for (int i = 0; i < k; i++) {
    cin >> g[i + 1];
  }
  g[k + 1] = s;
  sort(g, g + k + 2);
  int l = 0, r = 2e9 + 2;
  while (r - l > 1) {
    int m = (l + (r - l) / 2);
    bool f = 1;
    long long curt = 0;
    for (int i = 0; i < k + 1; i++) {
      if (g[i + 1] - g[i] > m) {
        f = 0;
        break;
      } else
        curt +=
            2 * (g[i + 1] - g[i]) - min(m - g[i + 1] + g[i], g[i + 1] - g[i]);
    }
    if (curt <= t && f) {
      r = m;
    } else {
      l = m;
    }
  }
  int mn = 2e9 + 2;
  for (int i = 0; i < n; i++) {
    if (v[i].second >= r) {
      mn = min(mn, v[i].first);
    }
  }
  if (mn == 2e9 + 2)
    cout << -1;
  else
    cout << mn;
  return 0;
}
