import java.util.Scanner;

public class Main{
	static double h,a,d;
	static double dp[];
	static double res(double x){
		if(x>=h) return 0;
		else if(dp[(int)x]!=-1) return dp[(int)x];
		else return Math.min(res(x+a)+1, res(x+d)+1.5);
	}
    public static void main(String[] args){
    	Scanner sc=new Scanner(System.in);
        while(sc.hasNext()){
        	h=sc.nextDouble();
        	a=sc.nextDouble();
        	d=sc.nextDouble();
        	dp=new double[(int)h+1];
        	for(int i=0;i<=h;i++) dp[i]=-1;
        	System.out.println(res(0));
        }
    }
}