Problem:
Score : 200 points

Problem Statement

A sequence a=\{a_1,a_2,a_3,......\} is determined as follows:

The first term s is given as input.

Let f(n) be the following function: f(n) = n/2 if n is even, and f(n) = 3n+1 if n is odd.

a_i = s when i = 1, and a_i = f(a_{i-1}) when i > 1.

Find the minimum integer m that satisfies the following condition:

There exists an integer n such that a_m = a_n (m > n).

Constraints

1 \leq s \leq 100

All values in input are integers.

It is guaranteed that all elements in a and the minimum m that satisfies the condition are at most 1000000.

Input

Input is given from Standard Input in the following format:

s

Output

Print the minimum integer m that satisfies the condition.

Sample Input 1

8

Sample Output 1

5

a=\{8,4,2,1,4,2,1,4,2,1,......\}. As a_5=a_2, the answer is 5.

Sample Input 2

7

Sample Output 2

18

a=\{7,22,11,34,17,52,26,13,40,20,10,5,16,8,4,2,1,4,2,1,......\}.

Sample Input 3

54

Sample Output 3

114

Solution in C++14 (GCC 5.4.1) (judge verdict: Accepted)

#include <bits/stdc++.h>
using namespace std;

int main(){
    int s,ans;cin>>s;
    vector<int> a(1000005);
    a.at(0)=s;
    for(int i=0;i<1000000;i++){
        if(a.at(i)%2==0){
            a.at(i+1)=a.at(i)/2;
        }
        else{
            a.at(i+1)=3*a.at(i)+1;
        }
    }
    for(int i=0;i<1000000;i++){
        if(a.at(i)==4){
            ans=i+4;
            break;
        }
    }
    if(s!=2&&s!=1) cout<<ans<<endl;
    else cout<<4<<endl;
}