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[200005], b[200005], c[200005];
int main() {
  int n, m, i, j, flag;
  long long s, t, l, r, mid, tim, ans;
  while (~scanf("%d%d%lld%lld", &n, &m, &s, &t)) {
    for (i = 0; i < n; i++) scanf("%lld%lld", &c[i], &a[i]);
    b[0] = 0;
    b[m + 1] = s;
    for (i = 1; i <= m; i++) scanf("%lld", &b[i]);
    sort(b, b + m + 2);
    l = 0;
    r = s * 2;
    while (l < r) {
      tim = 0;
      mid = (l + r) / 2;
      flag = 0;
      for (i = 0; i <= m; i++) {
        if (mid >= 2 * (b[i + 1] - b[i]))
          tim += b[i + 1] - b[i];
        else if (mid >= (b[i + 1] - b[i]))
          tim += mid - (b[i + 1] - b[i]) + (2 * (b[i + 1] - b[i]) - mid) * 2;
        else {
          flag = -1;
          break;
        }
      }
      if (tim > t || flag == -1)
        l = mid + 1;
      else
        r = mid - 1;
    }
    tim = 0;
    flag = 0;
    mid = (l + r) / 2;
    for (i = 0; i <= m; i++) {
      if (mid >= 2 * (b[i + 1] - b[i]))
        tim += b[i + 1] - b[i];
      else if (mid >= (b[i + 1] - b[i]))
        tim += mid - (b[i + 1] - b[i]) + (2 * (b[i + 1] - b[i]) - mid) * 2;
      else {
        flag = -1;
        break;
      }
    }
    if (tim > t || flag == -1) mid++;
    ans = 1000000001;
    for (i = 0; i < n; i++) {
      if (a[i] >= mid && c[i] < ans) ans = c[i];
    }
    if (ans == 1000000001) ans = -1;
    printf("%lld\n", ans);
  }
  return 0;
}
