#include<bits/stdc++.h> using namespace std; int main(){ float b; int a; cin>>a; if(a<=2){ b=6; cout<<b; } if(a>2){ if(a>10){ b=6+(10-2)*1.8; b=b+(a-10)*2.7; //printf("%.1f",b); cout << b; }else{ if(a==7){ b=6+(a-2)*1.8; cout<<b; }else{ b=6+(a-2)*1.8; cout<<b; } } } return 0; }