#include<bits/stdc++.h>
using namespace std;
int main(){
	int a;
	float s,d,k;
	cin>>a;
	s=a/100;
	d=a%100;
	k=(a+s+d)/3.0;
	printf("%.2f",k);
}
/**************************************************************
	Problem: 1618
	User: wangyiyang
	Language: C++
	Result: Accepted
	Time:7 ms
	Memory:2072 kb
****************************************************************/