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, t, s, g[1000005], mn = 999999999;
pair<int, int> p[1000005];
bool ok(int x) {
  int xx = p[x].first, time = 0;
  for (int i = 1; i <= k + 1; i++) {
    x = xx;
    int len = g[i] - g[i - 1];
    if (len > x) return false;
    time += min(len, x - len) + ((len - min(len, x - len)) * 2);
  }
  if (time > t) return false;
  return true;
}
int bin() {
  int l = 0, r = n;
  while (r - l > 1) {
    int md = (l + r) / 2;
    if (ok(md)) {
      r = md;
    } else
      l = md;
  }
  return r;
}
int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  cin >> n >> k >> s >> t;
  for (int i = 1; i <= n; i++) {
    cin >> p[i].second >> p[i].first;
  }
  for (int i = 1; i <= k; i++) {
    cin >> g[i];
  }
  sort(p + 1, p + 1 + n);
  sort(g + 1, g + 1 + k);
  g[k + 1] = s;
  int x = bin();
  if (x == 0)
    cout << -1;
  else {
    for (int i = x; i <= n; i++) {
      mn = min(p[i].second, mn);
    }
    cout << mn;
  }
}
