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 (
	"bufio"
	"os"
	"fmt"
)

func solve() {
	var N int
	Readf("%d", &N)

	var c float32 = float32(N/2)
	if (N % 2 ) == 1 {
		c++
	}

	Writef("%f", c/float32(N))
}

func main()  {
	// If io still contains some buffered data flush it before
	// quiting
	defer io.Flush()

	// Solution of the problem goes here
	solve()
}

var (
	// fmt.Print and fmt.Scan is slow, we will use bufio
	// for read and write from stdin.
	io = bufio.NewReadWriter(
		bufio.NewReader(os.Stdin),
		bufio.NewWriter(os.Stdout),
	)
)

func Readf(format string, args ...interface{})  {
	fmt.Fscanf(io, format, args...)
}

func Writef(format string, args ...interface{})  {
	fmt.Fprintf(io, format, args...)
}