#include<bits/stdc++.h> using namespace std; int main(){ int a; double b; b=6; cin>>a; if(a<=2){ b=6; } if(a>2&&a<=10){ b=(a-2)*1.8+6; }if(a>10){ b=8*1.8+(a-10)*1.8*1.5+6; } cout<<b; }