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

int main(){
  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];
  int as=a[s],at=a[t];
  if (as+at<=k) cout<<1<<endl;
  else{
    int am=*min_element(a.begin(),a.end());
    if (as+am<=k&&am+at<=k) cout<<2<<endl;
    else cout<<-1<<endl;
  }
}