import java.util.*;

public class Main {
  public static void main(String[] args) {
    Scanner sc = new Scanner(System.in);
    long t = sc.nextLong();
    long a = sc.nextLong();
    long b = sc.nextLong();

    long ans = 2 + (t - 1) / a;

    long g = gcd(a, b);
    long g1 = g * (a / g) * (b / g);

    ans -= (1 + (t - 1) / g1);

    ans += (t - 1) / b;

    System.out.println(ans);
  }

  public static long gcd(long a, long b) {
    if(b == 0) return a;
    return gcd(b, (a % b));
  }
}