【加1乘2平方】

#include<iostream>
#include<queue>
using namespace std;

int m,n;
int used[10005];
int step[10005];
queue <int> q;

int change(int now,int i)
{
    switch(i)
    {
        case 0:return now+1;
        case 1:return now*2;
        case 2:return now*now;
    }
    return -1;
}

int bfs()
{
    int now,next;
    while(!q.empty())
    {
        now=q.front();
        q.pop();
        for(int i=0;i<3;i++)
        {
            next=change(now,i);
            if(next<=n&&!used[next])    //越界！！！！！！
            {
                used[next]=1;
                step[next]=step[now]+1;
                if(next==n)
                    return step[next];
                else
                    q.push(next);
            }

        }
    }
    return -1;
}

int main()
{
    cin>>m>>n;
    q.push(m);
    used[m]=1;
    step[m]=0;
    cout<<bfs()<<endl;
    return 0;
}