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 long long MAXN = 2e5 + 22, INF = 1e10 + 7;
long long n, k, s, t, x, dis[MAXN], high, low, mid;
pair<long long, long long> car[MAXN];
bool check(long long ans) {
  if (ans < x) return false;
  long long u, e = 0;
  for (int i = 1; i <= k + 1; i++) {
    u = ans - dis[i] + dis[i - 1];
    if (u <= dis[i] - dis[i - 1])
      e += u + (2 * (dis[i] - dis[i - 1]) - ans) * 2;
    else
      e += dis[i] - dis[i - 1];
  }
  if (e <= t)
    return true;
  else
    return false;
}
int main() {
  ios_base::sync_with_stdio(false);
  cin >> n >> k >> s >> t;
  for (int i = 1; i <= n; i++) cin >> car[i].first >> car[i].second;
  dis[k + 1] = s;
  for (int i = 1; i <= k; i++) cin >> dis[i];
  sort(dis + 1, dis + 1 + k);
  sort(car + 1, car + 1 + n);
  for (int i = 1; i <= k + 1; i++) x = max(x, dis[i] - dis[i - 1]);
  low = 0, high = INF;
  while (high >= low) {
    mid = (low + high) / 2;
    if (check(mid))
      high = mid - 1;
    else
      low = mid + 1;
  }
  for (int i = 1; i <= n; i++) {
    if (car[i].second >= low) {
      cout << car[i].first;
      return 0;
    }
  }
  cout << -1;
  return 0;
}
