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 count = (t - 1) / a + (t - 1) / b;
		count -= (t - 1) / a / (b /gcd(a, b));
		System.out.println(count + 1);
	}
	
	static long gcd(long a, long b) {
	    if (a % b == 0) {
	        return b;
	    } else {
	        return gcd(b, a % b);
	    }
	}
}