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 GCC optimize("O2")
using namespace std;
const int MAXN = 1e6 + 10;
const long long MOD = 1e9 + 7;
const long long MOD2 = 998244353;
const long long INF = 8e18;
const int LOG = 20;
long long pw(long long a, long long b, long long mod) {
  return (!b ? 1
             : (b & 1 ? (a * pw(a * a % mod, b / 2, mod)) % mod
                      : pw(a * a % mod, b / 2, mod)));
}
int n, k, s, t;
vector<pair<int, int> > v;
vector<int> gas;
bool check(int x) {
  if (x >= n) return 0;
  long long ans = 0, last = v[x].first;
  for (int i = 1; i <= k + 1; i++) {
    int del = gas[i] - gas[i - 1];
    if (del > last) return 0;
    ans += 2 * (del);
    ans -= max(0ll, min(1ll * del, (last - del)));
  }
  if (ans > t) return 0;
  return 1;
}
int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  cout.tie(0);
  ;
  cin >> n >> k >> s >> t;
  for (int i = 1; i <= n; i++) {
    int a, b;
    cin >> a >> b;
    v.push_back(make_pair(b, a));
  }
  for (int i = 1; i <= k; i++) {
    int a;
    cin >> a;
    gas.push_back(a);
  }
  gas.push_back(s);
  gas.push_back(0);
  sort((gas).begin(), (gas).end());
  sort((v).begin(), (v).end());
  reverse((v).begin(), (v).end());
  int d = 0, up = n;
  while (up - d > 1) {
    int mid = (up + d) >> 1;
    if (check(mid)) {
      d = mid;
    } else {
      up = mid;
    }
  }
  if (check(0) == 0) {
    return cout << -1, 0;
  }
  int ans = 2e9;
  for (int i = 0; i <= d; i++) {
    ans = min(ans, v[i].second);
  }
  for (int i = 0; i < n; i++) {
  }
  cout << ans;
  return 0;
}
