import java.util.*;
 

public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int h = sc.nextInt();
		int a = sc.nextInt();
		int d = sc.nextInt();
		double [] dp = new double[20001];
		Arrays.fill(dp,0,10000,0);
		Arrays.fill(dp, 10001,20000,999999);
		for(int i=10001;i<20001;i++){
			dp[i]=Math.min(1+dp[i-a], 1.5+dp[i-d]);
		}
		System.out.println(dp[10000+h]);
	}
}