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