import java.io.InputStream;
import java.io.PrintWriter;
import java.lang.reflect.Array;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.HashSet;
import java.util.List;
import java.util.Scanner;
import java.util.Set;
import java.util.TreeSet;

import static java.util.Comparator.*;

public class Main {
    public static void main(String[] args) {
        PrintWriter out = new PrintWriter(System.out);
        Solver solver = new Solver(System.in, out);
        solver.solve();
        out.close();
    }
}
class Solver {
	Scanner sc;
	PrintWriter out;
    public Solver(InputStream in, PrintWriter out) {
    	sc = new Scanner(in);
    	this.out = out;
    }
    // 最大公約数の取得			
    long gcd(long a, long b) {			
    	if (b == 0)		
    		return a;	
    	return gcd(b, a % b);		
    }			
    			
    // 最小公倍数の取得			
    long lcm(long a, long b) {			
    	return a / gcd(a, b)  * b;		
    }			

    // ==================================================================
    public void solve() {
    	long T = Long.parseLong(sc.next());
    	long A = Long.parseLong(sc.next());
    	long B = Long.parseLong(sc.next());
    	if(T == 1) {
    		out.println(0);
    		return;
    	}
    	long ans = T / A - (T % A == 0 ? 1 : 0);
//    	out.println(ans);
    	ans += (T / B - (T % B == 0 ? 1 : 0));
//    	out.println(ans);
    	long L = lcm(A, B);
    	ans -= (T / L - (T % L == 0 ? 1 : 0));
    	out.println(ans+1);
    }
    // ==================================================================
}
class PP{
	public int key, val;
	public PP(int key, int val) {
		this.key = key;
		this.val = val;
	}
	public int getKey() {
		return key;
	}
	public int getVal() {
		return val;
	}
}