open System
type Sol() =
    member this.Solve() = 
        let ss = stdin.ReadLine().Split(' ')
        let (N,G,V) = (int ss.[0], double ss.[1], int ss.[2])
        N/5 |> double |> (*) G |> fun x -> x/(double V) |> printfn "%.12f" 

let mySol = new Sol()
mySol.Solve()