#include <bits/stdc++.h>
using namespace std;
#define int long long int
#define endl "\n" 
signed main(){
    ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0);
    int n,s,t,k;cin>>n>>s>>t>>k;
    vector<int> a(n+1);
    for(int i=1;i<=n;i++){
        cin>>a[i];
    }
    if(a[s]+a[t] <= k){
        cout<<1;
        return 0;
    }
    int mn = INT_MAX;
    for(int i=1;i<=n;i++){
        mn = min(mn,a[i]);
    }
    if(a[s]+mn <= k and a[t]+mn <= k){
        cout<<2;
        return 0;
    }
    cout<<-1;
    return 0;
}