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;
void Read(int &x) {
  char c;
  while (c = getchar(), c != EOF) {
    if (c >= '0' && c <= '9') {
      x = c - '0';
      while (c = getchar(), c >= '0' && c <= '9') x = x * 10 + c - '0';
      ungetc(c, stdin);
      return;
    }
  }
}
int n, k, s, t, bcnt, d[200000 + 10];
pair<int, int> a[200000 + 10], b[200000 + 10];
void read() {
  Read(n), Read(k), Read(s), Read(t);
  int i;
  for (i = 1; i <= n; i++) Read(a[i].second), Read(a[i].first);
  sort(a + 1, a + n + 1);
  for (i = 1; i <= k; i++) Read(d[i]);
  d[++k] = s;
  sort(d + 1, d + k + 1);
}
void solve() {
  int i;
  b[1] = a[1];
  for (i = 2; i <= n; i++) {
    while (bcnt && a[i].second <= b[bcnt].second) bcnt--;
    b[++bcnt] = a[i];
  }
}
bool check(int x) {
  int i, ret = 0;
  for (i = 1; i <= k; i++) {
    int now = d[i] - d[i - 1];
    if (now > b[x].first) return 0;
    ret += max(now * 2 - (b[x].first - now), now);
  }
  return ret <= t;
}
int Divide_Conqure(int l, int r) {
  int mid;
  while (l < r) {
    mid = (l + r) >> 1;
    if (check(mid))
      r = mid;
    else
      l = mid + 1;
  }
  return l;
}
int main() {
  read();
  solve();
  printf("%d\n", b[Divide_Conqure(1, bcnt)].second);
}
