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, t;
int c[300000], v[300000], g[300000];
int check(int p) {
  int d = g[0], cost = 0;
  if (p < d) return 0;
  if (p >= 2 * d)
    cost += d;
  else
    cost += 2 * (2 * d - p) + p - d;
  for (int i = 1; i <= k; i++) {
    d = g[i] - g[i - 1];
    if (p < d) return 0;
    if (p >= 2 * d)
      cost += d;
    else
      cost += 2 * (2 * d - p) + p - d;
  }
  return cost <= t;
}
int main() {
  scanf("%d%d%d%d", &n, &k, &s, &t);
  for (int i = 0; i < n; i++) scanf("%d%d", c + i, v + i);
  for (int i = 0; i < k; i++) scanf("%d", g + i);
  sort(g, g + k);
  g[k] = s;
  long long l = 0, r = 2 * s, mid;
  while (l + 1 < r) {
    mid = (l + r) / 2;
    if (check((int)mid))
      r = mid;
    else
      l = mid;
  }
  if (!check(r)) {
    printf("-1\n");
  } else {
    int minv = (int)r, ans = -1;
    for (int i = 0; i < n; i++)
      if (v[i] >= minv && (ans == -1 || (ans > 0 && c[i] < ans))) ans = c[i];
    printf("%d\n", ans);
  }
  return 0;
}
