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;
const int mod = 1000000007;
const int N = 3e5;
vector<int> g[N];
int a[N];
long long c[N], f[N];
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  long long i, k, j, s, n;
  long long t;
  cin >> n >> k >> s >> t;
  for (i = 0; i < n; i++) cin >> c[i] >> f[i];
  vector<int> A(k, 0);
  for (i = 0; i < k; i++) {
    cin >> A[i];
  }
  A.push_back(0);
  A.push_back(s);
  sort(A.begin(), A.end());
  multiset<pair<long long, long long> > my, fin;
  map<long long, long long> id;
  map<long long, int> no;
  long long mx = 0;
  for (i = 0; i < k + 1; i++) {
    long long val = A[i + 1] - A[i];
    mx = max(mx, val);
    my.insert({val, 2 * val});
    no[val]++;
  }
  int T = 1;
  long long pre = 0;
  for (auto x : no) pre += x.second, id[x.first] = pre;
  pre = 0;
  my.insert({0, 0});
  for (auto &cur : my) {
    pre += cur.second;
    fin.insert({cur.first, pre});
  }
  long long ans = mod * 1LL * mod;
  long long inf = ans;
  fin.insert({inf, inf});
  for (i = 0; i < n; i++) {
    if (f[i] < mx) continue;
    long long fuel = f[i];
    long long cur = 3 * s - (k + 1) * fuel;
    long long key = fuel / 2;
    auto it = fin.lower_bound({key, inf});
    if (it == fin.begin() or it == fin.end()) {
      if (cur <= t) ans = min(ans, c[i] + 0LL);
      continue;
    }
    if (it->first != key) it--;
    pair<long long, long long> add = *it;
    cur -= add.second;
    cur += fuel * id[add.first];
    if (cur <= t) ans = min(ans, c[i] + 0LL);
  }
  ans = ans == inf ? -1 : ans;
  cout << ans << endl;
  return 0;
}
