#include <bits/stdc++.h>
using namespace std;
// #include <atcoder/modint>
// using namespace atcoder;
// using mint = modint998244353;
using ll = long long;
#define fix(x) fixed << setprecision(x)
#define rep(i, n) for(int i = 0; i < n; ++i)
#define all(x) (x).begin(),(x).end()
template<class T>bool chmin(T&a, const T&b){if(a>b){a=b;return 1;}return 0;}
template<class T>bool chmax(T&a, const T&b){if(a<b){a=b;return 1;}return 0;}
constexpr ll INFLL = (1LL << 62), MOD = 998244353;
constexpr int INF = (1 << 30);

int main(){
    cin.tie(nullptr);
    ios::sync_with_stdio(false);
    int n,s,t,k;
    cin >> n >> s >> t >> k;
    --s, --t;
    int mi = INF;
    vector<int> a(n);
    rep(i,n) cin >> a[i], chmin(mi,a[i]);
    if(a[s]+a[t]<=k) cout << "1\n";
    else if(a[s]+mi<=k && mi+a[t]<=k) cout << "2\n";
    else cout << "-1\n";
    return 0;
}