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;
pair<int, int> arr[200005];
vector<int> g;
int main() {
  int i, j, k;
  int n, s, t;
  scanf("%d", &n);
  scanf("%d", &k);
  scanf("%d", &s);
  scanf("%d", &t);
  for (i = 1; i <= n; i++) {
    scanf("%d", &arr[i].first);
    scanf("%d", &arr[i].second);
  }
  for (i = 1; i <= k; i++) {
    scanf("%d", &j);
    g.push_back(j);
  }
  g.push_back(0);
  g.push_back(s);
  sort(g.begin(), g.end());
  int l = 0, r = 1e9;
  int ans = 1e9;
  while (l <= r) {
    int mid = (l + r) / 2;
    int temp = 0;
    for (i = 1; i < g.size(); i++) {
      int x = g[i] - g[i - 1];
      int a = 2 * x - mid;
      if (a < 0) {
        temp += x;
        continue;
      } else if (a > x) {
        break;
      } else
        temp += a + x;
    }
    if (i != g.size() || temp > t)
      l = mid + 1;
    else {
      ans = mid;
      temp = mid - 1;
      r = mid - 1;
    }
  }
  int ans2 = 2e9;
  for (i = 1; i <= n; i++) {
    if (arr[i].second >= ans) ans2 = min(ans2, arr[i].first);
  }
  if (ans2 == 2e9)
    printf("-1\n");
  else
    printf("%d\n", ans2);
  return 0;
}
