C++ :

#include<bits/stdc++.h>
using namespace std;
int main()
{
	int n,s=0;
	cin>>n;
	s=n;
	for(int t;n>=3;)
	{
		t=n/3;
		s+=t;
		t+=n%3;
		n=t;		
	} 
	cout<<s; 
	return 0;
}