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 maxn = 2e5 + 10;
long long g[maxn];
bool check(int n, int x, int t) {
  long long time = 0;
  for (int i = 1; i <= n; i++) {
    if (g[i] > x) return 0;
    long long now = 2ll * g[i];
    if (g[i] * 2 <= x) {
      time += g[i];
      continue;
    }
    long long rem = x - g[i];
    time += 2ll * g[i] - rem;
  }
  return time <= t;
}
pair<int, int> car[maxn];
int main() {
  ios_base::sync_with_stdio(false);
  int n, k, s, t;
  cin >> n >> k >> s >> t;
  for (int i = 1; i <= n; i++) cin >> car[i].first >> car[i].second;
  for (int i = 1; i <= k; i++) cin >> g[i];
  sort(g + 1, g + k + 1);
  g[k + 1] = s;
  for (int i = k + 1; i >= 1; i--) g[i] = g[i] - g[i - 1];
  k++;
  int lo = 0, hi = 2 * s;
  while (hi - lo > 1) {
    int mid = (1ll * lo + hi) >> 1;
    if (check(k, mid, t))
      hi = mid;
    else
      lo = mid;
  }
  int answer = -1;
  for (int i = 1; i <= n; i++)
    if (car[i].second >= hi)
      if (answer == -1 or answer > car[i].first) answer = car[i].first;
  cout << answer << endl;
}
