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.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.Iterator;

public class Main {

	public static void main(String[] args) throws IOException {
		// TODO 自動生成されたメソッド・スタブ
		int[] a = new int[1000000];
		int end = 0;
		int findex=0;
		int m = 100000;
		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
		String str = br.readLine();
		a[0]=Integer.parseInt(str);
		
		
		for(int i=0; i<a.length-1 ;i++){
			if (a[i]==1){
				end += 1;
				if(end==2){
					findex=i;
					break;
				}
			}
			if (a[i]%2 == 0){
				a[i+1]=a[i]/2;
			}
			else {
				a[i+1]=a[i]*3+1;
			}
		}
		
		for(int i=0; i<m; i++){
			for(int j=i+1; j<m; j++){
				if (a[i]==a[j]){
					m = j;
				}
			}
		}
		System.out.println(m+1);
	}
}