#include<bits/stdc++.h>
using namespace std;
int main()
{
	int a;
	cin>>a;
	int b=a;
	int c=a;
	while(b!=0)
	{
		b/=3;
		b=b+(a-b*3);
		c+=b;
	}
	cout<<c;
	return 0;
}