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.*;
import java.util.*;

public class Main {

    static class InputReader {
        BufferedReader reader;
        StringTokenizer tokenizer;

        public InputReader(InputStream stream) {
            reader = new BufferedReader(new InputStreamReader(stream), 32768);
            tokenizer = null; }
        String next() { while (tokenizer == null || !tokenizer.hasMoreTokens()) {
                try { tokenizer = new StringTokenizer(reader.readLine()); } 
                catch (IOException e) { throw new RuntimeException(e);} }
            return tokenizer.nextToken(); }
        public int nextInt() { return Integer.parseInt(next()); }
        public long nextLong() { return Long.parseLong(next()); }
        public double nextDouble() { return Double.parseDouble(next()); }
    }

    static InputReader r = new InputReader(System.in);
    static PrintWriter pw = new PrintWriter(System.out);

    public static void main(String[] args) {
        
        int n = r.nextInt();
        if(n % 2 == 0){
            pw.println(0.5);
        } else {
            pw.println(1.0 * (1 + (n/2)) / n);
        }

        pw.close();
    }
}

/**
                _        _                 _                                                
               | |      | |               | |                                               
   ___ ___   __| | ___  | |__  _   _    __| | __ _ _ __ _ __ ___ _ __     _   _  __ _  ___  
  / __/ _ \ / _` |/ _ \ | '_ \| | | |  / _` |/ _` | '__| '__/ _ \ '_ \   | | | |/ _` |/ _ \ 
 | (_| (_) | (_| |  __/ | |_) | |_| | | (_| | (_| | |  | | |  __/ | | |  | |_| | (_| | (_) |
  \___\___/ \__,_|\___| |_.__/ \__, |  \__,_|\__,_|_|  |_|  \___|_| |_|   \__, |\__,_|\___/ 
                                __/ |                               ______ __/ |            
                               |___/                               |______|___/             
 */