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;
long long a[205000];
long long c[200500], d[200500];
long long n, k, s, t;
bool check(int x) {
  long long l = 0, ans = 0;
  for (int i = 0; i < k; i++) {
    if (x < a[i] - l) return 0;
    ans += max(a[i] - l, 2 * (a[i] - l) - (x - a[i] + l));
    l = a[i];
  }
  return ans <= t;
}
int main() {
  ios::sync_with_stdio(0);
  cin >> n >> k >> s >> t;
  for (int i = 0; i < n; i++) cin >> c[i] >> d[i];
  for (int i = 0; i < k; i++) cin >> a[i];
  a[k] = s;
  k++;
  long long l = 0, r = 1e9, m;
  sort(a, a + k);
  while (l + 1 < r) {
    m = (l + r) / 2;
    if (!check(m)) {
      l = m;
    } else {
      r = m;
    }
  }
  long long ans = 1e9;
  for (int i = 0; i < n; i++) {
    if (d[i] >= r) ans = min(ans, c[i]);
  }
  if (ans == 1e9) {
    cout << -1;
    return 0;
  }
  cout << ans;
}
