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 C# (Mono 4.6.2.0) (judge verdict: Wrong Answer)

using System;
class Program
{
    static void Main(string[] args)
    {
        //// 整数の入力
        //int a = int.Parse(Console.ReadLine());
        //// スペース区切りの整数の入力
        //string[] input = Console.ReadLine().Split(' ');
        //int b = int.Parse(input[0]);
        //int c = int.Parse(input[1]);
        //// 文字列の入力
        //string s = Console.ReadLine();
        ////出力
        //Console.WriteLine((a + b + c) + " " + s);

        int a = int.Parse(Console.ReadLine());

        float answer = 0;
        if ( a % 2 != 0)
        {
            answer = (a - a / 2) / (float)a;
        }
        else
        {
            answer = 0.5f;
        }
    }
}