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 max_n = 222222, inf = 1111111111;
int n, k, s, t, a[max_n];
pair<int, int> p[max_n];
vector<pair<int, int> > v;
bool check(int v) {
  int last = 0, res = 0;
  for (int i = 0; i < k; ++i) {
    int len2 = a[i] - last;
    if (len2 > v) {
      return false;
    }
    int o = v - len2;
    int x = min(len2, o);
    int len1 = x;
    len2 -= x;
    res += len2 * 2 + len1;
    last = a[i];
  }
  return res <= t;
}
int main() {
  scanf("%d%d%d%d", &n, &k, &s, &t);
  for (int i = 0; i < n; ++i) {
    scanf("%d%d", &p[i].second, &p[i].first);
  }
  for (int i = 0; i < k; ++i) {
    scanf("%d", &a[i]);
  }
  a[k] = s;
  ++k;
  sort(a, a + k);
  sort(p, p + n);
  int l = -1, r = n;
  while (r - l > 1) {
    int mid = (l + r) / 2;
    if (check(p[mid].first)) {
      r = mid;
    } else {
      l = mid;
    }
  }
  if (r == n) {
    printf("-1\n");
    return 0;
  }
  int ans = p[r].second;
  for (int i = r; i < n; ++i) {
    ans = min(ans, p[i].second);
  }
  printf("%d\n", ans);
  return 0;
}
