defmodule Main do def make_list(number, result) when number == 2, do: result def make_list(number, result), do: make_list(number-1, [number|result]) def sieve([head|_], number) when rem(number, head) == 0, do: false def sieve([_|tail], number), do: sieve(tail, number) def sieve([], _), do: true def is_prime(number), do: make_list(trunc(:math.sqrt(number)), []) |> sieve(number) def every_call([_|tail], acc) when tail == [], do: acc def every_call([head|tail], acc) when head == 1, do: every_call(tail, acc) def every_call([head|tail], acc) do ls = [head|tail] |> Enum.map(fn(x) -> head * x end) |> Enum.concat(acc) every_call(tail, ls) end def main do i = IO.gets("") |> String.trim |> String.to_integer Stream.iterate(100000, &(&1+1)) |> Stream.filter(&is_prime/1) |> Enum.take(9) |> every_call([]) |> Enum.concat([1]) |> Enum.sort |> Enum.at(i-1) |> IO.puts end end