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

int main(){
    ios::sync_with_stdio(false);
    cin.tie(nullptr);

    int N,S,T,K;
    cin>>N>>S>>T>>K;
    S--;T--;
    int m=1e9;
    vector<int> A(N);
    for(int i=0;i<N;i++){
        cin>>A[i];
        m=min(m,A[i]);
    }
    if(A[S]+A[T]<=K){
        cout<<1<<"\n";
    }
    else if(A[S]+m<=K&&A[T]+m<=K)cout<<2<<"\n";
    else cout<<-1<<"\n";

}