open System

let zCount = function
    | x when x % 15 = 0 -> 4
    | x when x %  3 = 0 -> 2
    | x when x %  5 = 0 -> 2
    | x                 -> 0

let count = int(Console.ReadLine())
let n = Seq.initInfinite (fun i->i+1)
let z = Seq.map zCount n |> Seq.take count |> Seq.sum

printfn "%d" z