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 JavaScript (node.js v5.12) (judge verdict: Accepted)

process.stdin.resume();

var lines = [];
var reader = require("readline").createInterface({
  input: process.stdin,
  output: process.stdout
});

reader.on("line", line => {
  var num = parseInt(line);
  var odd = 0;
  for (var i = 1; i <= num; i++) {
    if (i % 2 !== 0) {
      odd++;
    }
  }
  p = odd / num;
  console.log(p);
});