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 maxN = 300000;
struct Node {
  int c, v;
} a[maxN + 1];
bool comp(Node x, Node y) {
  if (x.v != y.v) return x.v < y.v;
  return x.c < y.c;
}
int n, s, k, t, oil[maxN + 1], ans = -1, final = 2147483647;
bool check(int);
inline int read();
int main() {
  n = read();
  k = read();
  s = read();
  t = read();
  for (int i = 1; i <= n; i++) {
    a[i].c = read();
    a[i].v = read();
  }
  sort(a + 1, a + n + 1, comp);
  for (int i = 1; i <= k; i++) oil[i] = read();
  sort(oil + 1, oil + k + 1);
  k++;
  oil[k] = s;
  int l = 1, r = n;
  while (l <= r) {
    int mid = (l + r) / 2;
    if (check(mid)) {
      ans = mid;
      r = mid - 1;
    } else
      l = mid + 1;
  }
  if (ans == -1)
    printf("-1");
  else {
    for (int i = ans; i <= n; i++) final = min(final, a[i].c);
    printf("%d", final);
  }
  return 0;
}
inline int read() {
  int num = 0, f = 1;
  char ch = getchar();
  while ((ch < '0' || ch > '9') && ch != '-') ch = getchar();
  if (ch == '-') {
    f = -1;
    ch = getchar();
  }
  while (ch >= '0' && ch <= '9') {
    num = num * 10 + ch - '0';
    ch = getchar();
  }
  return num * f;
}
bool check(int num) {
  int ti = 0, loca = 0;
  for (int i = 1; i <= k; i++) {
    int dis = oil[i] - oil[i - 1];
    if (dis > a[num].v) return false;
    if (dis * 2 <= a[num].v)
      ti += dis;
    else {
      int rest = a[num].v - dis;
      ti = ti + dis * 2 - rest;
    }
    loca += dis;
  }
  if (ti > t) return false;
  return true;
}
