package yukicoder023;
import java.util.Arrays;
import java.util.Scanner;
public class Main {
	static int h,a,d;
	static double[] memo=new double[100000];
	public static void main(String[] args){
		Arrays.fill(memo, -1);
		Scanner sc=new Scanner(System.in);
		h=sc.nextInt();//敵の体力
		a=sc.nextInt();//通常攻撃の威力
		d=sc.nextInt();//必殺技の威力
		
		System.out.println(dp(h));
		sc.close();
	}
	public static double dp(int x){
		if(x<=0)return 0;
		if(memo[x]>=0)return memo[x];
		return memo[x]=Math.min(dp(x-a)+1,dp(x-d)+1.5);
	}

}