#include<bits/stdc++.h>
using namespace std;
int main() {
	int n,b,s,h;
	float j;
	cin>>n;
	s=n%100;
	b=n/100;
	j=(n+s+b)/3.0;
	printf("%.2f",j);
}

/**************************************************************
	Problem: 1618
	User: chenjunlin
	Language: C++
	Result: Accepted
	Time:7 ms
	Memory:2072 kb
****************************************************************/