#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: chenjiahui
	Language: C++
	Result: Accepted
	Time:10 ms
	Memory:2072 kb
****************************************************************/