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 Pascal (FPC 2.6.2) (judge verdict: Accepted)

VAR
  n, le : longint ;
  x, y : real ;
BEGIN
  readln(n) ;
  if n = 1 then 
    begin
      writeln('1.0000000000') ;
      halt ;
    end else
  if ( n mod 2 = 0 ) then le := n div 2 else le := n div 2 + 1 ;
  y := n ;
  x := le ;
  writeln(x/y:0:10) ;
END.