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 + 56;
const int inf = 1e9 + 7;
int c[N], v[N], l[N], p[N];
long long sum[N];
int main() {
  int n, k, s, t;
  cin >> 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", p + i);
  }
  sort(p, p + k);
  int now = 0;
  for (int i = 0; i < k; i++) {
    l[i] = p[i] - now;
    now = p[i];
  }
  l[k++] = s - now;
  sort(l, l + k);
  sum[0] = 0;
  for (int i = 0; i < k; i++) sum[i + 1] = sum[i] + l[i];
  int ans = inf;
  for (int i = 0; i < n; i++) {
    if (v[i] < l[k - 1]) continue;
    int id = upper_bound(l, l + k, v[i] / 2) - l;
    long long cur = sum[id] + (sum[k] - sum[id]) * 3 - 1LL * v[i] * (k - id);
    if (cur <= t) ans = min(ans, c[i]);
  }
  if (ans >= inf) ans = -1;
  printf("%d\n", ans);
  return 0;
}
