#include <cstdlib>
#include <iostream>

using namespace std;

int main()
{
int n,br;
cout<<„Unesi br reda cigli, n= „;
cin>>n;
if (n%2==0)
br=n/2*9;
else
br=(n-1)/2*9+5;
cout<<br<<endl;
system(„PAUSE“);
return EXIT_SUCCESS;
}