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

using ll = long long;

bool chmin(auto &a, auto b) { return a > b ? a = b, true : false; }
bool chmax(auto &a, auto b) { return a < b ? a = b, true : false; }

int main() {
    cin.tie(nullptr);
    ios::sync_with_stdio(false);

    int N, S, T, K; cin >> N >> S >> T >> K; --S, --T;
    vector<pair<int,int>> A(N);
    for(int i=0; i<N; ++i) {
        cin >> A[i].first;
        A[i].second = i;
    }
    sort(A.begin(), A.end());
    int s = -1, t = -1;
    for(int i=0; i<N && A[0].first + A[i].first <= K; ++i) {
        if(A[i].second == S) s = i;
        if(A[i].second == T) t = i;
    }
    if(s == -1 || t == -1) cout << -1 << '\n';
    else if(A[s].first + A[t].first <= K) cout << 1 << '\n';
    else cout << 2 << '\n';
}