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;
#pragma comment(linker, "/STACK:64000000")
const int infi = 1e9 + 7;
const long long infl = 1e18 + 7;
pair<long long, long long> ar[200500];
long long arz[200500];
long long get_time(long long d, long long v) {
  if (d > v) return 10LL * infi;
  long long l = 0, r = d, ans = -1;
  while (l <= r) {
    long long mid = (l + r) >> 1;
    long long cost = mid * 2 + d - mid;
    if (cost <= v) {
      ans = mid;
      l = mid + 1;
    } else
      r = mid - 1;
  }
  return ans + (d - ans) * 2;
}
int main() {
  cin.sync_with_stdio(false);
  cin.tie(0);
  long long n, k, s, t;
  cin >> n >> k >> s >> t;
  for (int i = 0; i < n; ++i) {
    cin >> ar[i].first >> ar[i].second;
  }
  for (int i = 0; i < k; ++i) cin >> arz[i];
  arz[k++] = s;
  sort(arz, arz + k);
  long long l = 0, r = 10LL * infi, ans = -1;
  while (l <= r) {
    long long mid = (l + r) >> 1;
    long long cur_t = 0;
    long long pos = 0;
    for (int i = 1; i < k; ++i) {
      long long d = arz[i] - pos;
      pos = arz[i];
      cur_t += get_time(d, mid);
    }
    if (cur_t <= t) {
      ans = mid;
      r = mid - 1;
    } else {
      l = mid + 1;
    }
  }
  if (ans == -1) {
    cout << -1;
  } else {
    int min_cost = infi;
    for (int i = 0; i < n; ++i) {
      if (ar[i].second >= ans) {
        min_cost = min(1LL * min_cost, ar[i].first);
      }
    }
    if (min_cost == infi) min_cost = -1;
    cout << min_cost;
  }
  return 0;
}
