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 main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  long long n, k, s, t;
  cin >> n >> k >> s >> t;
  vector<long long> c(n);
  vector<long long> v(n);
  for (int i = 0; i < n; ++i) cin >> c[i] >> v[i];
  vector<long long> g(k);
  for (int i = 0; i < k; ++i) cin >> g[i];
  g.push_back(0);
  sort(g.begin(), g.end());
  for (int i = 0; i < g.size() - 1; ++i) g[i] = g[i + 1] - g[i];
  g[g.size() - 1] = s - g[g.size() - 1];
  long long l = 1, r = INT_MAX;
  while (l <= r) {
    long long mid = (l + r) / 2;
    bool flag = true;
    long long min_time = 0;
    for (int i = 0; i < g.size(); ++i) {
      if (g[i] > mid) {
        flag = false;
        break;
      }
      if (g[i] * 2 <= mid)
        min_time += g[i];
      else {
        min_time += g[i] * 2 - (mid - g[i]);
      }
    }
    if (!flag || min_time > t)
      l = mid + 1;
    else
      r = mid - 1;
  }
  int ans = -1;
  for (int i = 0; i < n; ++i) {
    if (v[i] >= l && (ans == -1 || c[i] < ans)) ans = c[i];
  }
  cout << ans;
  return 0;
}
