AC

#include <bits/stdc++.h>
using namespace std;
int n,k,d[2000005];
queue<int>q;
int main(){
    cin>>n>>k;
    q.push(n);
    d[n]=1;
    while(!q.empty()){
        int x=q.front();
        q.pop();
        if(x==k){
            cout<<d[x]-1;
            break;
        }
        if(x-1>=1&&d[x-1]==0){
            d[x-1]=d[x]+1;
            q.push(x-1);
        }
        if(x+1<=2000000&&d[x+1]==0){
            d[x+1]=d[x]+1;
            q.push(x+1);
        } 
        if(x*2<=2000000&&d[x*2]==0){
            d[x*2]=d[x]+1;
            q.push(x*2);
        } 
    }
	return 0;
}