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.io.BufferedReader;
import java.io.*;
import java.util.*;
public class Main {
	public static void main(String[] args) throws IOException {
		BufferedReader br = new BufferedReader(
			new InputStreamReader(System.in));
		try {
			double n = Double.parseDouble(br.readLine());
			if(n % 2 == 0) {
				System.out.println(String.format("%.7f", 1.0 / 2));
			} else {
				System.out.println(String.format("%.7f", ((n + 1) / 2) / n));
			}
			br.close();
		} catch(IOException e) {
			e.printStackTrace();
		}
	}
}