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

#define rep(i, a, b) for (ll i = a; i < b; i++)
using ll = long long;

int main() {
	ll n, s, t, k;
	cin >> n >> s >> t >> k;
	s--, t--;
	vector<int> a(n);
	int mi = 1e9 + 1;
	rep(i, 0, n) {
		cin >> a[i];
		if(i != s && i != t) mi = min(mi, a[i]);
	}
	int av = a[s];
	int tv = a[t];
	int ans = -1;
	if(av + tv <= k) ans = 1;
	else {
		if(av + mi <= k && mi + tv <= k) ans = 2;
	}
	cout << ans << endl;
}