using System.Numerics;
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]);
        getAns(t, a, b);
    }
    static void getAns(long t, long a, long b)
    {
        var gcd = Gcd(a, b);
        BigInteger lcm = (BigInteger)a / gcd * b;
        var a1 = (t - 1) / a + 1;
        var a2 = (t - 1) / b + 1;
        var a3 = (t - 1) / lcm + 1;
        Console.WriteLine(a1 + a2 - a3);
    }
    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;
    }
}