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 int arr[200002];
long long int arr1[200002];
long long int arr2[200002];
long long int g[200002];
long long int n, s, k, t, i, j, d;
long long int binarySearch() {
  long long int beg = 0;
  long long int l, m = 0, p;
  long long int end = n, mid;
  while (beg <= end) {
    m = 0;
    long long int time = 0;
    mid = (beg + end) / 2;
    for (i = 0; i < k; i++) {
      p = g[i] - m;
      if (arr[mid] >= p) {
        if (2 * p - arr[mid] >= 0) {
          time += (2 * p - arr[mid]) * 2 + arr[mid] - p;
        } else {
          time += p;
        }
      } else {
        time += 10000000000000;
      }
      m = g[i];
    }
    p = s - m;
    if (arr[mid] >= p) {
      if (2 * p - arr[mid] >= 0) {
        time += (2 * p - arr[mid]) * 2 + arr[mid] - p;
      } else {
        time += p;
      }
    } else {
      time += 10000000000000;
    }
    if (time == t) {
      return arr[mid];
    } else if (time > t) {
      beg = mid + 1;
    } else {
      end = mid - 1;
    }
  }
  if (beg >= 0 && beg < n) {
    return arr[beg];
  } else {
    return -1;
  }
}
int main() {
  long long int a, b, min = 10000000000002, z;
  cin >> n >> k >> s >> t;
  for (i = 0; i < n; i++) {
    cin >> a >> b;
    arr[i] = b;
    arr1[i] = b;
    arr2[i] = a;
  }
  for (i = 0; i < k; i++) {
    cin >> g[i];
  }
  sort(arr, arr + n);
  sort(g, g + k);
  z = binarySearch();
  if (z != -1) {
    for (i = 0; i < n; i++) {
      if (arr1[i] >= z) {
        if (arr2[i] <= min) {
          min = arr2[i];
        }
      }
    }
    cout << min;
  } else {
    cout << -1;
  }
  return 0;
}
