#include<bits/stdc++.h> using namespace std; int main(){ int a; double p; cin>>a; if(a<=2){ p = 6; } if(a>2&&a<=10){ p = 6+(a-2)*1.8; } if(a>10){ p = 6+8*1.8+(a-10)*(1.8*1.5); } cout<<p; return 0; }