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 MAX_N = 200001;
const int MAX_K = 200001;
struct Node {
  int c;
  int v;
};
int n, k, s, t;
Node a[MAX_N];
int b[MAX_N];
int Min(int num1, int num2) {
  if (num1 < num2) return num1;
  return num2;
}
bool Cmp(Node &node1, Node &node2) {
  if (node1.v < node2.v)
    return true;
  else if (node1.v == node2.v)
    return node1.c <= node2.c;
  return false;
}
int Calc(int idx) {
  int minT = 0;
  for (int i = 0; i <= k; ++i) {
    int dist = b[i + 1] - b[i];
    int maxY = a[idx].v - dist;
    int minY = Min(maxY, dist);
    if (minY < 0) return -1;
    minT += 2 * dist - minY;
  }
  if (minT > t) return -1;
  return 1;
}
int BSearch() {
  b[k + 1] = s;
  int st = 0;
  int end = n - 1;
  while (st <= end) {
    int mid = (st + end) >> 1;
    int ret = Calc(mid);
    if (ret >= 0)
      end = mid - 1;
    else
      st = mid + 1;
  }
  return st;
}
int main() {
  scanf("%d %d %d %d", &n, &k, &s, &t);
  for (int i = 0; i < n; ++i) scanf("%d %d", &a[i].c, &a[i].v);
  for (int i = 1; i <= k; ++i) scanf("%d", &b[i]);
  sort(a, a + n, Cmp);
  int minC = -1;
  for (int i = n - 1; i >= 0; --i) {
    if (minC == -1) {
      minC = a[i].c;
      break;
    }
    if (a[i].c >= minC) {
      --n;
      swap(a[i], a[n]);
    } else {
      minC = a[i].c;
    }
  }
  sort(a, a + n, Cmp);
  sort(b + 1, b + k + 1);
  int idx = BSearch();
  printf("%d\n", a[idx].c);
  return 0;
}
