// #pragma GCC optimize ("Ofast")
// #pragma GCC optimize ("unroll-loops")
// #pragma GCC target ("avx,avx2,fma")
#include <bits/stdc++.h>

using std::cin, std::cout, std::cerr;
using ll = long long;

int main() {
    std::ios::sync_with_stdio(false);
    int n, s, t, k;
    cin >> n >> s >> t >> k;
    std::vector<int> a(n + 1);
    for(int i = 1; i <= n; i ++)
        cin >> a[i];
    int min = *std::min_element(a.begin() + 1, a.end());
    if(a[s] + a[t] <= k) cout << 1 << '\n';
    else if(a[s] + min <= k && a[t] + min <= k) cout << 2 << '\n';
    else cout << -1 << '\n';
}