using System;
using static System.Console;
using System.Linq;
using System.Collections.Generic;


class Program
{
    static int NN => int.Parse(ReadLine());
    static long[] NList => ReadLine().Split().Select(long.Parse).ToArray();
    public static void Main()
    {
        Solve();
    }
    static void Solve()
    {
        var c = NList;
        var (t, a, b) = (c[0], c[1], c[2]);
        WriteLine(Bus(t, a, b));
    }
    static long Bus(long t, long a, long b)
    {
        var ans = (t + a - 1) / a + (t + b - 1) / b;
        var gcd = GCD(a, b);
        var lcm = a / gcd * b;
        if (lcm % b == 0 && lcm / b == a / gcd) ans -= (t + lcm - 1) / lcm;
        else --ans;
        return ans;
    }
    static long GCD(long a, long b)
    {
        if (a < b) return GCD(b, a);
        if (a % b == 0) return b;
        return GCD(b, a % b);
    }
}