#include<bits/stdc++.h>
using namespace std;
int main(){
	float j,i;
	int x;
	cin>>x;
	j=x%100;
	i=x/100;
	n=(i+j+x)/3.0;
	printf("%.2f",n);
}
/**************************************************************
	Problem: 1618
	User: wangyiyang
	Language: C++
	Result: Compile Error
****************************************************************/