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;
vector<long long int> refill;
long long int t;
bool check(long long int v) {
  long long int tt = 0;
  for (int i = 1; i < refill.size(); i++) {
    if (v < refill[i] - refill[i - 1]) {
      return false;
    }
    tt += 3 * (refill[i] - refill[i - 1]) -
          min(v, 2 * (refill[i] - refill[i - 1]));
    if (tt > t) {
      return false;
    }
  }
  return true;
}
int main() {
  long long int n, k, s;
  cin >> n >> k >> s >> t;
  vector<pair<long long int, long long int>> cars_cost;
  vector<long long int> cars_fuel;
  for (int i = 0; i < n; i++) {
    int a, b;
    cin >> a >> b;
    cars_cost.push_back({a, b});
    cars_fuel.push_back(b);
  }
  sort(cars_cost.begin(), cars_cost.end());
  sort(cars_fuel.begin(), cars_fuel.end());
  refill.reserve(k + 2);
  refill.push_back(0);
  refill.push_back(s);
  for (int i = 0; i < k; i++) {
    int l = 0;
    cin >> l;
    refill.push_back(l);
  }
  sort(refill.begin(), refill.end());
  long long int l = -1;
  long long int r = n;
  while (r - l > 1) {
    long long int m = l + (r - l) / 2;
    if (check(cars_fuel[m])) {
      r = m;
    } else {
      l = m;
    }
  }
  if (r >= cars_fuel.size() - 1 || !check(cars_fuel[r])) {
    cout << "-1" << endl;
    return 0;
  }
  long long int minim = 10e16;
  long long int fuel = cars_fuel[r];
  for (auto i : cars_cost) {
    if (i.second >= fuel) {
      minim = min(minim, i.first);
    }
  }
  cout << minim << endl;
  return 0;
}
