using System;

public class Hello
{
    static void Main()
    {
        string[] line = Console.ReadLine().Trim().Split(' ');
        var n = long.Parse(line[0]);
        var a = int.Parse(line[1]);
        var b = int.Parse(line[2]);
        getAns(n, a, b);
    }
    static void getAns(long n, int a, int b)
    {
        var g = gcd(a, b);
        var Lcm = (long)a * b / g;
        var ans = n - n / a - n / b + n / Lcm;
        Console.WriteLine(ans);
    }
    static int gcd(int a, int b)
    {
        if (a < b) return gcd(b, a);
        while (b != 0)
        {
            var w = a % b;
            a = b;
            b = w;
        }
        return a;
    }
}