open System open System.Collections.Generic [] module Cin = let read f = stdin.ReadLine() |> f let reada f = stdin.ReadLine().Split() |> Array.map f let readChars() = read string |> Seq.toArray let readInts() = readChars() |> Array.map (fun x -> Convert.ToInt32(x.ToString())) [] module Cout = let writer = new IO.StreamWriter(new IO.BufferedStream(Console.OpenStandardOutput())) let print (s: string) = writer.Write s let println (s: string) = writer.WriteLine s let inline puts (s: ^a) = string s |> println [] module Prime = let limit n = n |> float |> sqrt |> int let inline isPrime (n: int) = let lim = limit n seq { for p in 2 .. lim do if n % p = 0 then yield () } |> Seq.isEmpty let isheihou n = seq { for i in 2 .. (limit n) do if i * i = n then yield () } |> Seq.isEmpty |> not let isripou n = seq { for i in 2 .. (limit n) do if i * i * i = n then yield () } |> Seq.isEmpty |> not let divisors (n: int64): int64 array = let lim = n |> float |> sqrt |> int64 seq { for i in 1L .. lim do if n % i = 0L then yield i if i * i <> n then yield n / i } |> Array.ofSeq |> Array.sort let divsum n = divisors n |> Array.sum let solve() = let n = read int64 divsum n |> puts () [] let main _ = try solve() with e -> failwithf "%s" (e.ToString()) writer.Close() 0 // return an integer exit code