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

#define rep(i,n) for(int i = 0; i < n; ++i)
using ll = long long;

int main(void) {
    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;
    	return 0;
    }
    
    int Amin = 2e9;
    rep(i,N) Amin = min(Amin, A[i]);
    if(Amin + A[T] <= K and Amin + A[S] <= K) {
    	cout << 2 << endl;
    } else{
    	cout << -1 << endl;
    }
    
    return 0;
}