#include<bits/stdc++.h>
using namespace std;
int main() {
	int n,a,b;
	cin>>n;
	a=n/100;
	b=n%100;
	printf("%.2f",(n+a+b)/3.0);
}
/**************************************************************
	Problem: 1618
	User: linzihang
	Language: C++
	Result: Accepted
	Time:8 ms
	Memory:2072 kb
****************************************************************/