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;
const int maxn = 1e6 + 10, inf = 1e9;
const long double pi = 3.14159265;
long long n, k, s, t;
long long gas[maxn];
vector<pair<long long, long long> > a;
bool check(long long mid) {
  vector<long long> distance;
  distance.push_back(0);
  distance.push_back(s);
  for (int i = 0; i < k; i++) {
    distance.push_back(gas[i]);
  }
  sort(distance.begin(), distance.end());
  long long fuel = mid, time = 0;
  for (int i = 1; i < distance.size(); i++) {
    long long dis = distance[i] - distance[i - 1];
    if (dis > fuel)
      return 0;
    else {
      long long tmp = min(dis, fuel - dis);
      time += tmp + (dis - tmp) * 2;
    }
  }
  if (time > t) {
    return 0;
  }
  return 1;
}
int main() {
  ios::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  cin >> n >> k >> s >> t;
  for (int i = 0; i < n; i++) {
    long long x, y;
    cin >> x >> y;
    a.push_back(make_pair(y, x));
  }
  for (int i = 0; i < k; i++) {
    cin >> gas[i];
  }
  sort(a.begin(), a.end());
  long long l = 0, r = t * 2;
  while (l < r - 1) {
    long long mid = (l + r) / 2;
    if (check(mid) == 1) {
      r = mid;
    } else {
      l = mid;
    }
  }
  long long ans = 9e9;
  if (check(r) == 0) {
    return cout << -1, 0;
  }
  for (int i = 0; i < a.size(); i++) {
    if (a[i].first >= r) {
      ans = min(ans, a[i].second);
    }
  }
  if (ans == 9e9) {
    return cout << -1, 0;
  }
  cout << ans << endl;
  return 0;
}
