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 int N = 200100;
const int INF = 0x63636363;
int n, k, s, t;
int c[N], v[N];
int g[N];
bool ok(int fuel) {
  int pos = 0;
  long long total_time = 0;
  for (int i = 0; i <= k; i++) {
    if (g[i] - pos > fuel) {
      return false;
    }
    if (fuel >= 2 * (g[i] - pos)) {
      total_time += g[i] - pos;
    } else {
      long long rem = fuel % (g[i] - pos);
      total_time += rem + 2 * (g[i] - pos - rem);
    }
    pos = g[i];
  }
  return total_time <= t;
}
int main() {
  scanf("%d%d%d%d", &n, &k, &s, &t);
  for (int i = 0; i < n; i++) {
    scanf("%d%d", &c[i], &v[i]);
  }
  for (int i = 0; i < k; i++) {
    scanf("%d", &g[i]);
  }
  sort(g, g + k);
  g[k] = s;
  int begin = 1, end = 2 * s;
  while (begin != end) {
    int mid = (begin + end) / 2;
    if (ok(mid)) {
      end = mid;
    } else {
      begin = mid + 1;
    }
  }
  int minimum = INF;
  for (int i = 0; i < n; i++) {
    if (v[i] >= begin && c[i] < minimum) {
      minimum = c[i];
    }
  }
  printf("%d\n", minimum == INF ? -1 : minimum);
  return 0;
}
