open System

let input = Console.ReadLine().Split(' ') |> Array.map int64
let n = input.[0]
let a = input.[1]
let b = input.[2]

// Count integers from 0 to N that are neither multiples of A nor multiples of B
let multiples_of_a = n / a + 1L
let multiples_of_b = n / b + 1L

// LCM of A and B
let rec gcd x y = if y = 0L then x else gcd y (x % y)
let lcm x y = x * y / (gcd x y)
let lcm_ab = lcm a b
let multiples_of_both = n / lcm_ab + 1L

// Using inclusion-exclusion principle
let result = (n + 1L) - multiples_of_a - multiples_of_b + multiples_of_both
printfn "%d" result