#include<iostream> #include<cstdio> #include<cstring> #include<cmath> using namespace std; int main(){ int a; float b; cin>>a; if(a>10){ b=(a-10)*1.8*1.5+(10-2)*1.8+6; }else if(a>2){ b=(a-2)*1.8+6; }else{ b=6; } cout<<b<<endl; return 0; }