using System;

public class Hello
{
    static void Main()
    {
        string[] line = Console.ReadLine().Trim().Split(' ');
        var t = long.Parse(line[0]);
        var a = long.Parse(line[1]);
        var b = long.Parse(line[2]);
        var gcd = Gcd(a, b);
        var tpa = t / a;
        if (t % a == 0) tpa--;
        var tpb = t / b;
        if (t % b == 0) tpb--;
        var tpLcm = t * gcd / a / b;
        if ((t * gcd / a) % b == 0) tpLcm--;
        var ans = tpa + tpb + 1 - tpLcm;
        Console.WriteLine(ans);
    }
    static long Gcd(long a, long b)
    {
        if (a < b) return Gcd(b, a);
        while (b != 0)
        {
            var w = a % b;
            a = b;
            b = w;
        }
        return a;
    }
}