import java.util.*;
import java.math.*;

public class Main
{
    public static void main(String[] args) throws Exception
	{
		Scanner scanner = new Scanner(System.in);
		
		BigDecimal t = scanner.nextBigDecimal();
		BigDecimal x = scanner.nextBigDecimal();
		BigDecimal y = scanner.nextBigDecimal();
		BigDecimal z = lcm(x, y);
		
		scanner.close();
		
		BigDecimal ans = BigDecimal.ZERO;
		
		ans = ans.add(t.divide(x, BigDecimal.ROUND_UP));
		ans = ans.add(t.divide(y, BigDecimal.ROUND_UP));
		ans = ans.subtract(t.divide(z, BigDecimal.ROUND_UP));
		
		System.out.println(ans.toPlainString());
    }
    
    private static BigDecimal gcd(BigDecimal x, BigDecimal y)
	{
		if (x.compareTo(y) < 0)
			return _gcd(y, x);
		
		return _gcd(x, y);
	}
	
	private static BigDecimal _gcd(BigDecimal x, BigDecimal y)
	{
		BigDecimal r = x.remainder(y);
		if(r.compareTo(BigDecimal.ZERO) == 0)
			return y;
		
		return _gcd(y, r);
	}
	
	private static BigDecimal lcm(BigDecimal x, BigDecimal y)
	{
	    return x.multiply(y).divide(gcd(x, y));
	}
}