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>
#pragma comment(linker, "/STACK:1000000000")
using namespace std;
const int maxn = (int)2e5 + 10;
pair<int, int> v[maxn];
int pos[maxn];
int n, k, s, t;
bool check(int sp) {
  int now = 0;
  long long tm = 0;
  for (int i = 0; i < k; i++) {
    int x = pos[i] - now;
    int b = sp - x;
    int a = 0;
    if (sp < x) {
      return false;
    }
    if (b < 0) {
      b = 0;
      a = x;
    } else if (b > x) {
      b = x;
    } else {
      a = x - b;
    }
    tm += 2 * a + b;
    now = pos[i];
  }
  return tm <= t;
}
int main() {
  cin >> n >> k >> s >> t;
  for (int i = 0; i < n; i++) {
    scanf("%d %d", &v[i].second, &v[i].first);
  }
  sort(v, v + n);
  for (int i = 0; i < k; i++) {
    scanf("%d", &pos[i]);
  }
  sort(pos, pos + k);
  pos[k] = s;
  k++;
  int l = 0;
  int r = n;
  while (l != r) {
    int m = (l + r) / 2;
    if (check(v[m].first)) {
      r = m;
    } else {
      l = m + 1;
    }
  }
  if (l == n) {
    cout << -1 << endl;
    return 0;
  }
  int ans = v[l].second;
  for (int i = l + 1; i < n; i++) {
    ans = min(ans, v[i].second);
  }
  cout << ans << endl;
  return 0;
}
