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 ans = (H + A - 1) / A; if(A < D) { double[] dp = new double[H + 1]; for(int i = 1; i <= A; i++) { dp[i] = 1; } for(int i = A + 1; i <= D; i++) { dp[i] = 1.5; } for(int i = D + 1; i < H + 1; i++) { dp[i] = Math.min(1 + dp[i - A], 1.5 + dp[i - D]); } ans = dp[H]; } System.out.println(ans); } }