简单模拟题;
#include<iostream>
using namespace std;
int sum;
int main()
{
int n;
scanf("%d",&n);
int c=n;
while(1)
{
int t=n/3;
sum+=t;
n=(n/3)+(n%3);
if(n<=2) break;
}
cout<<c+sum;
return 0;
}