import java.util.*;

public class Main {
	public static void main (String[] args) {
		Scanner sc = new Scanner(System.in);
		int[] inputs = new int[] {0,
                                    12345,
                                    67891,
                                    1112,
                                    13141,
                                    51617,
                                    18192,
                                    2122,
                                    23242,
                                    52627,
                                    28293,
                                    3132,
                                    33343,
                                    53637,
                                    38394,
                                    4142,
                                    43444,
                                    54647,
                                    48495,
                                    5152,
                                    53545,
                                    55657,
                                    58596,
                                    6162,
                                    63646,
                                    56667,
                                    68697,
                                    7172,
                                    73747,
                                    57677,
                                    78798,
                                    8182,
                                    83848,
                                    58687,
                                    88899,
                                    9192,
                                    93949,
                                    59697,
                                    98991};
		int n = sc.nextInt();
		int length = inputs.length;
		int prev = 0;
		for (int i = length - 1; i >= 0; i--) {
		    inputs[i] = inputs[i] * n + prev;
		    prev = inputs[i] / 100000;
		    inputs[i] %= 100000;
		}
		StringBuilder sb = new StringBuilder();
		sb.append(inputs[0]).append(".");
		for (int i = 1; i < length; i++) {
		    sb.append(String.format("%05d", inputs[i]));
		}
		System.out.println(sb);
	}
}