#include<bits/stdc++.h> 
using namespace std; 
int main()
{ 
 double a; 
 cin>>a; 
 if(a<=10) 
  cout<<fixed<<setprecision(2)<<a8.00; 
 else 
  cout<<fixed<<setprecision(2)<<a8.00*0.75; 
 return 0; 
}