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 pb          push_back
#define m_p			make_pair
#define rep(i,a,b)	for(int i=a;i<b;i++)
#define sz(x)       (int)x.size()
#define f			first
#define debug		cout<<"##########3"<<endl
#define mod			1000000007
#define ll			long long int
#define lMax		LLONG_MAX
// queue<int> , prefix_sum(a,a+n) , reverse(a,a+n) , priority_queue <int> max heap , priority_queue <int, vector<int>, greater<int> > min heap;
// == precedence gretaer then &
ll n,m;
string s,s1,s2;
priority_queue <long long int> pq;
map<ll, char> mp;
vector<pair<int,int> > inc;
vector<pair<int,int> > de;
ll arr[300005],barr[300005];
//EG
int main() {
    ios::sync_with_stdio(false);
    cin.tie(NULL);
	cout.tie(NULL);
	int i,j,k,z,ans=0,c=0,x=0,y=0;
	
	cin>>n;
	if(n%2==0)
		cout<<0.5000;
	else{
		x = n/2+1;
		long double q = x/double(n);
		cout<<setprecision(12)<<q;
	}
 	return 0;
}