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)); } } }