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 N = 2e5 + 5;
pair<long long int, long long int> a[N];
long long s, t;
long long int gas[N];
int n, k, s1, t1;
bool valid(long long m) {
  int tim = 0;
  for (int i = 2; i <= k; i++) {
    long long int l = gas[i] - gas[i - 1];
    if (m < l) return false;
    int tans = 0;
    if (m >= 2LL * l) {
      tim += l;
      continue;
    }
    long long x = 2LL * l - m;
    tim += (l + x);
  }
  return (tim <= t);
}
int main() {
  scanf("%d%d%d%d", &n, &k, &s1, &t1);
  t = t1;
  s = s1;
  for (int i = 1; i <= n; i++) scanf("%I64d%I64d", &a[i].second, &a[i].first);
  for (int i = 1; i <= k; i++) scanf("%I64d", &gas[i]);
  gas[k + 1] = 0;
  gas[k + 2] = s;
  k += 2;
  sort(gas + 1, gas + k + 1);
  long long int lo = 0, hi = 1e15;
  long long int ans = hi;
  while (lo <= hi) {
    long long int mid = (lo + hi) / 2;
    if (valid(mid)) {
      ans = min(ans, mid);
      hi = mid - 1;
    } else
      lo = mid + 1;
  }
  long long int cmin = 1e9 + 10;
  for (int i = 1; i <= n; i++) {
    if (a[i].first >= ans) {
      cmin = min(cmin, a[i].second);
    }
  }
  if (cmin == (int)(1e9 + 10)) cmin = -1;
  cout << cmin << endl;
  return 0;
}
