#include <stdio.h>
#include <atcoder/all>
#include <bits/stdc++.h>
using namespace std;
using namespace atcoder;
using mint = modint998244353;
#define rep(i,n) for (int i = 0; i < (n); ++i)
#define Inf32 1000000005
#define Inf64 1000000000000000001LL


int main(){
	
	int N,S,T,K;
	cin>>N>>S>>T>>K;
	S--,T--;
	vector<int> a(N);
	rep(i,N)cin>>a[i];
	if(a[S] + a[T] <= K){
		cout<<1<<endl;
	}
	else if(max(a[T],a[S]) + (*min_element(a.begin(),a.end())) <= K){
		cout<<2<<endl;
	}
	else{
		cout<<-1<<endl;
	}
	
}