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 n, k, s, tt;
int c[200005], v[200005], t[200005];
long long rui[200005];
int main() {
  cin >> n >> k >> s >> tt;
  for (int i = 1; i <= n; i++) {
    scanf("%d%d", &c[i], &v[i]);
  }
  for (int i = 0; i < k; i++) {
    scanf("%d", &t[i]);
  }
  sort(t, t + k);
  vector<int> vec;
  vec.push_back(t[0] - 0);
  for (int i = 1; i < k; i++) vec.push_back(t[i] - t[i - 1]);
  vec.push_back(s - t[k - 1]);
  sort(vec.begin(), vec.end());
  int ans = 1000000000;
  rui[0] = vec[0];
  for (int i = 1; i < vec.size(); i++) rui[i] = rui[i - 1] + 1LL * vec[i];
  for (int i = 1; i <= n; i++) {
    if (v[i] < vec[vec.size() - 1]) continue;
    int f = (v[i]) / 2;
    int d = upper_bound(vec.begin(), vec.end(), f) - vec.begin();
    d--;
    long long sum = rui[d];
    sum += (rui[vec.size() - 1] - rui[d]) * 3LL -
           1LL * (vec.size() - d - 1) * v[i];
    if (sum <= tt) ans = min(ans, c[i]);
  }
  if (ans == 1000000000) ans = -1;
  cout << ans << endl;
}
