#include <string>
#include <vector>

using namespace std;

int solution(int num) {
    int answer = 0;
    long long tmpNum = num;
    long long count = 0;
    
    if(num == 1){
        return answer;
    }
    while(true){
        if(tmpNum%2==0){ //even
            tmpNum/=2;
            count++;
            if(tmpNum == 1 && count <= 500) {
                answer = count;
                break;
            } else if(tmpNum!=1&&count >=500){
                answer = -1;
                break;
            }
        } else if(tmpNum%2!=0.0){ //odd
            tmpNum = tmpNum*3 + 1;
            count++;
            if(tmpNum == 1 && count <= 500) {
                answer = count;
                break;
            } else if (tmpNum!=1&&count >= 500){
                answer = -1;
                break;
            }
        }
    }
    
    return answer;
}