#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;
}