n, s, t, k = gets.not_nil!.split.map(&.to_i)
s -= 1
t -= 1

arr = Array(Int32).new(n)
gets.not_nil!.split.each do |num|
  arr << num.to_i
end

if arr[s] + arr[t] <= k
  puts "1"
else
  mina = arr.min
  if arr[s] + mina <= k && mina + arr[t] <= k
    puts "2"
  else
    puts "-1"
  end
end