#include <bits/stdc++.h>
using namespace std;
#define rep(i, n) for (int i = 0; i < (n); ++i)
using ll = long long;
using ull = unsigned long long;

int main() {
  cin.tie(nullptr)->sync_with_stdio(false);
  int n, s, t, k;
  cin >> n >> s >> t >> k;
  --s, --t;
  vector<int> a(n);
  rep(i, n) cin >> a[i];
  int minim = *min_element(a.begin(), a.end());
  if (minim + a[s] > k || minim + a[t] > k) {
    cout << -1 << '\n';
  }
  else if (a[s] + a[t] <= k) {
    cout << 1 << '\n';
  }
  else {
    cout << 2 << '\n';
  }
  return 0;
}