import java.util.*;

public class Main {
    static double[] dp;
    static int a;
    static int d;
	public static void main (String[] args) {
		Scanner sc = new Scanner(System.in);
		int h = sc.nextInt();
		a = sc.nextInt();
		d = sc.nextInt();
		dp = new double[h + 1];
		System.out.println(dfw(h));
   }
   static double dfw(int power) {
       if (power <= 0) {
           return 0;
       }
       if (dp[power] != 0) {
           return dp[power];
       }
       dp[power] = Math.min(dfw(power - a) + 1, dfw(power - d) + 1.5);
       return dp[power];
   }
}