open System

let ri () = stdin.ReadLine() |> int
let rla () = stdin.ReadLine().Split() |> Array.map int64

type Sol() =
    member this.Solve() = 
        let [|T; A; B|] = rla()
        
        let rec gcd a b = if a = 0L then b else gcd (b % a) a
        
        T / A + T / B - T / (A /(gcd A B) * B)
        |> printfn "%d"
        
        
        ()
let mySol = new Sol()
mySol.Solve()