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++14 (GCC 5.4.1) (judge verdict: Accepted)

#include<bits/stdc++.h>

using namespace  std;

#define ll long long

#define DEBUG(x) cerr << '>' << #x << ':' << x << endl;


int main(){
     
    double e=0,o=0,n;
    cin>>n;
    for (int i = 1; i<=n; ++i)
    {
        if(i%2==0){
            e+=1;
        }
        else{
            o+=1;
        }
    }
    double r;
    r=o/n;
   cout<<fixed<<setprecision(6)<<r;
 //cerr<<"\nTime Elapsed: " << 1.0*clock() / CLOCKS_PER_SEC << " sec\n";
    return 0;
}