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, c[200001], v[200001], g[200001];
int cost(int dist, int x) {
  if (dist * 2 <= x)
    return dist;
  else if (dist > x)
    return t + 1;
  else
    return -x + dist + dist + dist;
}
bool can(int x) {
  long long sum = cost(g[1], x);
  for (int i = 2; i <= k; i++) sum += cost(g[i] - g[i - 1], x);
  sum += cost(s - g[k], x);
  return sum <= t;
}
int main() {
  scanf("%d %d %d %d", &n, &k, &s, &t);
  for (int i = 1; i <= n; i++) scanf("%d %d", &c[i], &v[i]);
  for (int i = 1; i <= k; i++) scanf("%d", &g[i]);
  sort(g + 1, g + 1 + k);
  int s = 1, e = 1e9, ans = 1e9 + 1;
  while (s <= e) {
    int mid = (s + e) / 2;
    if (can(mid))
      ans = mid, e = mid - 1;
    else
      s = mid + 1;
  }
  int ret = 1e9 + 1;
  for (int i = 1; i <= n; i++)
    if (v[i] >= ans) ret = min(ret, c[i]);
  if (ret == 1e9 + 1) ret = -1;
  printf("%d", ret);
  return 0;
}
