#include <bits/stdc++.h>
using namespace std;
using ll = long long;

int main() {
    ios::sync_with_stdio(false);
    cin.tie(0);
    int n, s, t, k;
    cin >> n >> s >> t >> k;
    if(s == t){
        cout << "0\n";
        return 0;
    }
    vector<int> a(n);
    for(auto &&v : a) cin >> v;
    s = a[s - 1], t = a[t - 1];
    if(s + t <= k){
        cout << "1\n";
        return 0;
    }
    int mn = *min_element(a.begin(), a.end());
    if(s + mn <= k && t + mn <= k){
        cout << "2\n";
    }else{
        cout << "-1\n";
    }
}