TLE了,求救!!!

#include<bits/stdc++.h>

using namespace std;

int main()
{
    int a;
    int b=0;
    cin>>a;
    while(a!=1)
    {
        if(a % 2==0)a/=2;
        else a = a*3+1;
        b++;
    }
    cout<<b;
    return 0;
}

R140026646

哪里有问题,可以优化?