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 = 200005, INF = 2e9;
int n, k, s, t;
int cost[N], capacity[N], station[N];
bool enough(int c) {
  int travelTime = 0;
  int last = 0;
  for (int i = 1; i <= k; i++) {
    int d = station[i] - last;
    if (c < d) {
      return false;
    }
    int acc = min(d, c - d);
    travelTime += acc + 2 * (d - acc);
    last = station[i];
  }
  int d = s - last;
  if (c < d) {
    return false;
  }
  int acc = min(d, c - d);
  travelTime += acc + 2 * (d - acc);
  return travelTime <= t;
}
int main() {
  scanf("%d %d %d %d", &n, &k, &s, &t);
  for (int i = 1; i <= n; i++) {
    scanf("%d %d", &cost[i], &capacity[i]);
  }
  for (int i = 1; i <= k; i++) {
    scanf("%d", &station[i]);
  }
  sort(station + 1, station + 1 + k);
  int low = 1;
  int high = 2 * s;
  int res = high;
  while (low <= high) {
    int mid = ((long long)low + high) / 2;
    if (enough(mid)) {
      res = mid;
      high = mid - 1;
    } else {
      low = mid + 1;
    }
  }
  int best = INF;
  for (int i = 1; i <= n; i++) {
    if (capacity[i] >= res) {
      best = min(best, cost[i]);
    }
  }
  if (best == INF) {
    printf("-1\n");
  } else {
    printf("%d\n", best);
  }
  return 0;
}
