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.*;
import java.io.*;

class Main {

	void solve () {

		int a = in.nextInt();
		
		if (a%2 == 0) System.out.println(0.5);
		else {
			double b = a/2 + 1;
			double c = a;
			System.out.println(String.format("%.6f", b/c));
		}
		
	}

	public static PrintWriter out = new PrintWriter(System.out);
	public static Scanner in = new Scanner(System.in);
	public static void main(String[] args) {
		new Main().solve();
		out.flush();
	}

}