# include<iostream> using namespace std; int main(){ int b; cin>>b; if(2>=b){ cout<<6; } if(b>2&&b<=10){ cout<<6+(b-2)*1.8; } if(b>10){ cout<<6+(10-2)*1.8+(b-10)*1.8*1.5; } return 0; } /*罗子童 Accepted*/