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>
#include<vector>
#include<algorithm>
#include<utility>
#include<map>
#include<queue>
#include <cstdlib>
#include <climits>
#include <iomanip>
#include<iostream>
#include <sstream>  // for string streams
#include <string>  // for string
#include <stack> 
#include <cmath>
  #pragma comment(linker, "/STACK:2000000")
#pragma comment(linker, "/HEAP:2000000")
  using namespace std;
  #define IOS ios::sync_with_stdio(0); cin.tie(0); cout.tie(0);
  #define endl "\n"
  #define int long long
  #define all(v) v.begin(),v.end()
  #define rep(i,a,b) for(int i = a; i <=b; i++)
  #define rep2(i,a,b) for(int i = a; i>=b; i--)
  #define f first
  #define s second
  #define PB push_back
  #define MP make_pair
  #define db long double
  #define trace1(x)                cerr<<#x<<": "<<x<<endl
  #define trace2(x, y)             cerr<<#x<<": "<<x<<" | "<<#y<<": "<<y<<endl
  #define trace3(x, y, z)          cerr<<#x<<":" <<x<<" | "<<#y<<": "<<y<<" | "<<#z<<": "<<z<<endl
  #define trace4(a, b, c, d)       cerr<<#a<<": "<<a<<" | "<<#b<<": "<<b<<" | "<<#c<<": "<<c<<" | "<<#d<<": "<<d<<endl
  #define trace5(a, b, c, d, e)    cerr<<#a<<": "<<a<<" | "<<#b<<": "<<b<<" | "<<#c<<": "<<c<<" | "<<#d<<": "<<d<<" | "<<#e<< ": "<<e<<endl
  #define trace6(a, b, c, d, e, f) cerr<<#a<<": "<<a<<" | "<<#b<<": "<<b<<" | "<<#c<<": "<<c<<" | "<<#d<<": "<<d<<" | "<<#e<< ": "<<e<<" | "<<#f<<": "<<f<<endl
  #define cases int testcases;cin>>testcases; while(testcases--)
  #define MOD 1000000007
  void printprecise(double l,int precision) 
  {
    std::cout << std::fixed;
    std::cout << std::setprecision(precision);
    std::cout << l;
}

  vector<int> primes;
  
int32_t main()
{
       

 
  


   int n;
   cin >> n;
   int ans = n/2;
   if(n%2!=0)
   {
    ans++;
   }

   
   printprecise((db)((db)(ans)/(db)(n)),10);

    return 0;
}