#include <bits/stdc++.h>
#define int long long
using namespace std;
const int inf=1e18;
signed  main(){
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    int n,s,t,k;cin>>n>>s>>t>>k;
    s--;t--;
    vector<int>a(n);
    for(int i=0;i<n;i++)cin>>a[i];
    if(a[s]>k||a[t]>k){
        cout<<-1<<endl;
        return 0;
    }
    if(a[s]+a[t]<=k){
        cout<<1<<endl;
        return 0;
    }
    auto it=min_element(a.begin(),a.end());
    if(a[s]+*it<=k&&*it+a[t]<=k){
        cout<<2<<endl;
    }else{
        cout<<-1<<endl;
    }
}