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 Java8 (OpenJDK 1.8.0) (judge verdict: Accepted)

import java.util.*;

public class Main {

    public static void main(String[] args) {

        Scanner sc = new Scanner(System.in);

        int s = sc.nextInt();
        /*
         * 配列に出現した数をsetに格納する
         * setに存在するならその時のiを算出してreturn
         * */

        int[] arr = new int[1000000];
        arr[0] = s;
        Set<Integer> set = new HashSet<>();
        set.add(s);

        for (int i = 1; i < 1000000000; i++) {
            if (arr[i - 1] % 2 == 0) {
                arr[i] = arr[i - 1] / 2;
            } else {
                arr[i] = arr[i - 1] * 3 + 1;
            }

            if (set.contains(arr[i])) {
                System.out.println(i + 1);
                return;
            } else {
                set.add(arr[i]);
            }

        }

    }
}