#include <bits/stdc++.h>

using namespace std;

typedef long long ll;
typedef pair<ll,ll> P;
#define REP(i,n) for(ll i=0;i<ll(n);i++)










int main(void){
	cin.tie(nullptr);  ios_base::sync_with_stdio(false);
	ll i,j;




	ll N,S,T,K;
	cin >> N >> S >> T >> K;
	vector<ll> a(N);
	REP(i,N) cin >> a[i];

	ll p=a[S-1],q=a[T-1];


	sort(a.begin(),a.end());

	if(p+q<=K) cout << 1 << endl;
	if(a[0]+p<=K && a[0]+q<=K) cout << 2 << endl;
	else cout << -1 << endl;









	return 0;

}