# include<iostream> # include<iomanip> using namespace std; int main(){ int a; cin>>a; if(a<=2){ cout<<float(6); } if(a>2&&a<10){ cout<<float(6+(a-2)*1.8); } if(a>=10){ cout<<float(6+1.8*(10-2)+1.8*1.5*(a-10)); } return 0; }