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

int main() {
	int N, S, T, K; cin >> N >> S >> T >> K;
	S--; T--;
	
	vector<int> A(N);
	for (int i = 0; i < N; i++) cin >> A[i];
	
	int Amin = *min_element(A.begin(), A.end());
	if (A[S] + A[T] <= K) {
		cout << 1 << endl;
	}
	else if (A[S] + Amin <= K and A[T] + Amin <= K) {
		cout << 2 << endl;
	}
	else {
		cout << -1 << endl;
	}
}