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

int main(){
  int n,s,g,m; cin >> n >> s >> g >> m; --s,--g; vector<int> A(n); for (int& a:A) cin >> a;
  if (A[s]+A[g]<=m) cout << 1 << endl;
  else if (max(A[s],A[g])+*min_element(A.begin(),A.end())<=m) cout << 2 << endl;
  else cout << -1 << endl;
}