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;
long long mod = 1000000000 + 7;
vector<long long> g(200007);
long long n, k, s, t;
vector<long long> c(200008), v(200008);
long long check(long long mid) {
  long long tm = 0, dist = 0;
  dist = g[0];
  if (mid < dist)
    return 0;
  else if (mid >= (2 * dist)) {
    tm += dist;
  } else {
    long long add = 3 * dist - mid;
    if (add < 0)
      return 0;
    else
      tm += add;
  }
  for (long long i = 1; i < k; i++) {
    dist = g[i] - g[i - 1];
    if (mid < dist)
      return 0;
    else if (mid >= (2 * dist)) {
      tm += dist;
    } else {
      long long add = 3 * dist - mid;
      if (add < 0)
        return 0;
      else
        tm += add;
    }
  }
  dist = s - g[k - 1];
  if (mid < dist)
    return 0;
  else if (mid >= (2 * dist))
    tm += dist;
  else {
    long long add = 3 * dist - mid;
    if (add < 0)
      return 0;
    else
      tm += add;
  }
  if (tm > t)
    return 0;
  else
    return 1;
}
int32_t main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  cout.tie(NULL);
  cin >> n >> k >> s >> t;
  for (long long i = 0; i < n; i++) cin >> c[i] >> v[i];
  for (long long i = 0; i < k; i++) cin >> g[i];
  sort(g.begin(), g.begin() + k);
  long long st = 1, ed = 1000000000, mid, prevmid = -1, midans = -1;
  while (st <= ed) {
    mid = st + (ed - st) / 2;
    if (check(mid) == 1) {
      ed = mid - 1;
      midans = mid;
    } else
      st = mid + 1;
  }
  if (midans == -1) {
    cout << -1;
    return 0;
  } else {
    mid = midans;
  }
  long long ans = LONG_MAX, idx = -1;
  for (long long i = 0; i < n; i++) {
    if (v[i] >= mid) {
      idx = 1;
      ans = min(ans, c[i]);
    }
  }
  if (idx == -1)
    cout << -1;
  else
    cout << ans;
  return 0;
}
