Problem:
Score : 100 points

Problem Statement

Given is an integer N.

Takahashi chooses an integer a from the positive integers not greater than N with equal probability.

Find the probability that a is odd.

Constraints

1 \leq N \leq 100

Input

Input is given from Standard Input in the following format:

N

Output

Print the probability that a is odd.
Your output will be considered correct when its absolute or relative error from the judge's output is at most 10^{-6}.

Sample Input 1

4

Sample Output 1

0.5000000000

There are four positive integers not greater than 4: 1, 2, 3, and 4. Among them, we have two odd numbers: 1 and 3. Thus, the answer is \frac{2}{4} = 0.5.

Sample Input 2

5

Sample Output 2

0.6000000000

Sample Input 3

1

Sample Output 3

1.0000000000

Solution in Java8 (OpenJDK 1.8.0) (judge verdict: Accepted)

import java.util.Scanner;

public class Main {
	public static void main(String[] args){
//		整数 
//		N
//		 が与えられます。
//
//		高橋君は、
//		N
//		 以下の正整数の中から等確率で 
//		1
//		 つを選んで 
//		a
//		 とします。
//
//		このとき、
//		a
//		 が奇数である確率を答えてください。

		Scanner sc = new Scanner(System.in);
		double num = sc.nextInt();
		double odd = Math.ceil(num/2);
		double result = odd / num;
		System.out.println(result);
		sc.close();
	}
}