open System

let rec gcd [ a; b ] =
    match a % b with
    | 0 -> b
    | rest -> gcd [ b; rest ]

[<EntryPoint>]
let main argv =
    Console.ReadLine().Split ' '
    |> Array.toList
    |> List.map int
    |> List.sortDescending
    |> gcd
    |> Console.WriteLine

    0