//#pragma GCC optimize("Ofast")
//#pragma GCC optimize("unroll-loops")
#include <bits/stdc++.h>
using namespace std;
using ll = long long;





void solve(){
    int N, S, T, K; cin >> N >> S >> T >> K;
    vector<int> A(N);
    for(int i = 0; i < N; ++i) cin >> A[i];
    --S, --T;
    if(A[S] + A[T] <= K){
        cout << 1 << "\n";
        return;
    }
    int s = A[S];
    int t = A[T];
    sort(begin(A), end(A));
    if(s + A[0] <= K && A[0] + t <= K){
        cout << 2 << "\n";
    }else{
        cout << -1 << "\n";
    }
}

int main(){
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    cout << setprecision(10) << fixed;

    int T;
    T = 1;
    //cin >> T;
    for(;T--;) solve();
}