#include <bits/stdc++.h>
using namespace std;
using ll = long long;
#define rep(i, s, t) for (ll i = s; i < (ll)(t); i++)
#define all(x) begin(x), end(x)

template <class T> bool chmin(T& x, T y) {
	return x > y ? (x = y, true) : false;
}
template <class T> bool chmax(T& x, T y) {
	return x < y ? (x = y, true) : false;
}

struct io_setup {
	io_setup() {
		ios::sync_with_stdio(false);
		cin.tie(nullptr);
		cout << fixed << setprecision(15);
	}
} io_setup;

void solve() {
	int n, s, t, k;
	cin >> n >> s >> t >> k;
	s--, t--;
	vector<int> a(n);
	rep(i, 0, n) cin >> a[i];
	if (a[s] + a[t] <= k) {
		cout << "1\n";
	} else {
		int mn = *min_element(a.begin(), a.end());
		if (a[s] + mn <= k && a[t] + mn <= k) cout << "2\n";
		else cout << "-1\n";
	}
}

int main() {
	int t = 1;
	// cin >> t;
	while (t--) solve();
}