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;
long long INF = 1000000000000;
int main() {
  ios::sync_with_stdio(false);
  cin.tie(nullptr);
  int n, k;
  long long s, t;
  cin >> n >> k >> s >> t;
  vector<int> c(n), v(n);
  for (int i = 0; i < n; i++) {
    cin >> c[i] >> v[i];
  }
  vector<int> g(k);
  for (int i = 0; i < k; i++) {
    cin >> g[i];
  }
  g.push_back(0);
  g.push_back(s);
  k += 2;
  sort(g.begin(), g.end());
  long long tv = INF;
  long long fv = 0;
  while (tv - fv > 1) {
    long long mid = (tv + fv) / 2;
    long long time = 0;
    bool ok = true;
    for (int i = 0; i < k - 1; i++) {
      long long d = g[i + 1] - g[i];
      if (mid < d) {
        ok = false;
      } else if (mid > d * 2) {
        time += d;
      } else {
        time += 3 * d - mid;
      }
    }
    if (ok && time <= t) {
      tv = mid;
    } else {
      fv = mid;
    }
  }
  long long ans = INF;
  for (int i = 0; i < n; i++) {
    if (v[i] >= tv) {
      ans = min(ans, (long long)c[i]);
    }
  }
  if (ans == INF) {
    cout << -1 << endl;
  } else {
    cout << ans << endl;
  }
}
