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 inf = 0x3f3f3f3f;
const int mod = 1e9 + 10;
const int N = 2e5 + 10;
int n, k, s, t;
struct Node {
  int c, v;
  bool operator<(const Node &a) const {
    if (a.v != v) return c < a.c;
    return v < a.v;
  }
} a[N];
int b[N];
bool ok(int x) {
  int now = 0, tt = 0;
  for (int i = 0; i <= k; i++) {
    int dis = b[i] - now;
    now = b[i];
    if (x < dis) return 0;
    if (x >= dis * 2)
      tt += dis;
    else
      tt = tt + dis * 3 - x;
    if (tt > t) return 0;
  }
  return true;
}
int main() {
  scanf("%d%d%d%d", &n, &k, &s, &t);
  for (int i = 1; i <= n; i++) scanf("%d%d", &a[i].c, &a[i].v);
  sort(a + 1, a + 1 + n);
  for (int i = 1; i <= k; i++) scanf("%d", &b[i]);
  b[0] = s;
  sort(b, b + 1 + k);
  int l = 0, r = mod;
  while (l <= r) {
    int mid = l + r >> 1;
    if (!ok(mid))
      l = mid + 1;
    else
      r = mid - 1;
  }
  int ans = l;
  if (a[n].v < ans)
    printf("-1\n");
  else {
    int ret = inf;
    for (int i = n; i; i--) {
      if (a[i].v >= ans)
        ret = min(ret, a[i].c);
      else
        break;
    }
    printf("%d\n", ret);
  }
  return 0;
}
