#include<bits/stdc++.h>
using namespace std;
int main(){
	int n;
	float s,a,b;
	cin>>n;
	a=n*n;
	b=n*2-1+4;
	s=b/a*100.0;
	printf("%.1f",s);
	cout<<"%";
}
/**************************************************************
	Problem: 1345
	User: toughuatao1
	Language: C++
	Result: Accepted
	Time:10 ms
	Memory:2072 kb
****************************************************************/