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 Go (1.6) (judge verdict: Accepted)

package main

import "fmt"

func main() {
	//変数の定義
	var N int
	//変数の読み込み %dは整数を表す。
	fmt.Scanf("%d", &N)
	//Nが奇数かどうかの判定。yは奇数となる確率を表す。
	//x := N % 2
	//Nの余りを計算。偶数ならｘは0。奇数ならxは1。
	//条件分岐
	if N%2 == 1 {
		fmt.Printf("%.10f", (float64(N+1)/2)/float64(N))
	} else {
		fmt.Printf("%.10f", float64(0.5))
	}
	//	i := N
	//	d := i / 3
	//	m := i % 3
	//	fmt.Println(d, m)

	// 参考
	//var a, b int
	//var calc string

	//fmt.Printf("Please enter the calculation formula.\n")
	//fmt.Printf("ex) 1 + 1 = ? -> 1 1 +\n")
	//fmt.Scanf("%d %d %s", &a, &b, &calc)

	//fmt.Printf("%d %s %d = ", a, calc, b)
}