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 (GCC 5.4.1) (judge verdict: Accepted)

#include"stdio.h"
#include"stdlib.h"
int main(void){
  int input,odd;
  int tmp;
  scanf("%d",&input);
  tmp = input / 2;
  //printf("%d\n",tmp);
  if(input%2!=0){
    //奇数
    odd = tmp + 1;
  }
  else{
    //偶数
    odd = tmp;
    //printf("0.5",odd);
    //return 0;
  }
  
  printf("%.10f\n",(double)odd/(double)input);
  return 0;
}