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;
template <class T>
inline void smax(T &first, T second) {
  first = max((first), (second));
}
template <class T>
inline void smin(T &first, T second) {
  first = min((first), (second));
}
const int maxn = 2e5 + 100, inf = 1e9 + 7;
int c[maxn], v[maxn];
vector<int> first;
long long ps[maxn];
inline long long sm(int l, int r) {
  if (r < l) return 0;
  return ps[r] - (l ? ps[l - 1] : 0);
}
int main() {
  int n, k, s, t;
  scanf("%d %d %d %d", &n, &k, &s, &t);
  int mx = 0;
  for (int(i) = (0); (i) < (n); ++(i)) scanf("%d %d", c + i, v + i);
  for (int(i) = (0); (i) < (k); ++(i)) {
    int a;
    scanf("%d", &a);
    first.push_back(a);
  }
  first.push_back(s);
  first.push_back(0);
  sort(first.begin(), first.end());
  vector<int> second;
  for (int(i) = (1); (i) < (first.size()); ++(i)) {
    smax(mx, first[i] - first[i - 1]);
    second.push_back(first[i] - first[i - 1]);
  }
  sort(second.begin(), second.end());
  long long sum = 0;
  for (int(i) = (0); (i) < (second.size()); ++(i)) {
    sum += second[i];
    ps[i] = sum;
  }
  int ans = inf;
  for (int(i) = (0); (i) < (n); ++(i)) {
    if (v[i] < mx) continue;
    int e = upper_bound(second.begin(), second.end(), v[i] / 2) -
            second.begin() - 1;
    long long g = sm(0, e);
    long long cnt = max(0, (int)second.size() - e - 1);
    g += cnt * v[i] - sm(e + 1, (int)second.size() - 1);
    long long T = 2LL * sum - g;
    if (T <= t) smin(ans, c[i]);
  }
  cout << (ans == inf ? -1 : ans) << endl;
}
