#include<iostream> using namespace std; int main(){ double sum1; int a; cin>>a; if(a<2){ sum1=6; }else{ if(a>2&&a<=10){ sum1=(a-2)*1.8+6; }else{ if(a>10){ sum1=(10-2)*1.8+(a-10)*1.8*1.5+6; } } } cout<<sum1;