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 inf = 1e18;
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  cout.tie(NULL);
  long long n, k, s, t;
  cin >> n >> k >> s >> t;
  long long g[200005];
  long long cc[200005];
  long long vv[200005];
  for (int i = 0; i < n; i++) {
    cin >> cc[i] >> vv[i];
  }
  for (int i = 1; i <= k; i++) {
    cin >> g[i];
  }
  g[0] = 0;
  g[k + 1] = s;
  sort(g, g + k + 1);
  long long dif[200005];
  for (int i = 0; i < k + 1; i++) {
    dif[i] = g[i + 1] - g[i];
  }
  sort(dif, dif + k + 1);
  long long mini = inf;
  long long maxi = 0;
  long long low = 1;
  long long high = 1e10;
  while (low <= high) {
    long long mid = (low + high) / 2;
    bool b = true;
    long long tt = 0;
    for (int i = 0; i < k + 1; i++) {
      if (dif[i] > mid) b = false;
      tt += max(3 * dif[i] - mid, dif[i]);
    }
    if (b && tt <= t) {
      high = mid - 1;
    } else {
      low = mid + 1;
    }
  }
  for (int i = 0; i < n; i++) {
    if (vv[i] >= low) {
      mini = min(mini, cc[i]);
    }
  }
  if (mini == inf)
    cout << -1 << endl;
  else
    cout << mini << endl;
}
