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 n = 0, k = 0, s = 0, t = 0;
pair<int, int> cars[200002];
int gas[200002];
bool check(int index) {
  int v = cars[index].first;
  int pos = 0, time = 0;
  for (int i = 0; i <= k; i++) {
    if (time > t || gas[i] - pos > v) return false;
    int left = 0, right = gas[i] - pos + 1;
    while (left != (right - 1)) {
      int middle = (left + right) >> 1;
      if (middle * 2 + (gas[i] - pos - middle) <= v)
        left = middle;
      else
        right = middle;
    }
    time += left + (gas[i] - pos - left) * 2;
    pos = gas[i];
  }
  if (time > t) return false;
  return true;
}
int main() {
  scanf("%d%d%d%d", &n, &k, &s, &t);
  for (int i = 0; i < n; i++) scanf("%d%d", &cars[i].second, &cars[i].first);
  sort(cars, cars + n);
  for (int i = 0; i < k; i++) scanf("%d", gas + i);
  sort(gas, gas + k);
  gas[k] = s;
  if (!check(n - 1)) {
    printf("-1\n");
    return 0;
  }
  int left = -1, right = n - 1;
  while (left != (right - 1)) {
    int middle = (left + right) >> 1;
    if (check(middle))
      right = middle;
    else
      left = middle;
  }
  int min_c = cars[right].second;
  for (int i = right + 1; i < n; i++)
    if (cars[i].second < min_c) min_c = cars[i].second;
  printf("%d\n", min_c);
  return 0;
}
