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 (Clang 3.8.0) (judge verdict: Runtime Error)

//Warmdust Code
#include<iostream>
#include<cstdio>
#include<iomanip>
#include<algorithm>
#include<cstring>
#include<cstdlib>
#include<ctime>
#include<cmath>
#include<string>
#include<vector>
#include<queue>
#include<map>
#include<set>
#define db double
#define ll long long
#define ull unsigned long long
#define ft float
#define PI acos(-1)
#define L(i,a,b) for(int i=a;i<=b;i++)
#define R(i,a,b) for(int i=a;i>=b;i--)
#define inf 0x3f3f3f3f
#define linf  0x3f3f3f3f3f3f3f3f
#define Warmdust int main(){
#define RETURN return 0;}
#define TvT ios::sync_with_stdio(false),cin.tie(0),cout.tie(0);
using namespace std;
const int maxn = 100+7;
const int mod = 10000+7;
Warmdust
	TvT;
	int n;
	//cin >> n;
	scanf("%lld",&n);
	int a=n;
	if(n%2==1) n++;
	double s=n/2;
	printf("%.10llf\n",s/a);
RETURN