#include <iostream>
using namespace std;
/*
思路:输入n瓶水,n/3=z表换几瓶水,n%3=m得到剩下的空瓶子,m= m+ z,如果m大于3,则得到m/3瓶水;如果m等于2,则向老板接一个空瓶子,喝完水换一瓶水还给
老板;如果m等于1或0瓶水,则无法继续交换
*/
void PressurizedBottle(int n)
{
if(n == 0) {
return;
}
int m = 0;
int countNum = 0;
while(n>1) {
if(n == 2) {
countNum += 1;
break;
}
m = n % 3;
n /= 3;
countNum += n;
n += m;
}
cout<<countNum<<endl;
}
int main()
{
int n;
while(cin>>n) {
PressurizedBottle(n);
}
return 0;
}