int main(){
	int x,y,p;									//????
	cin>>x>>y;									//?????
    if(x==y)cout<<x<<endl;						//???????????
	else {										//???????
		if(x<y){
			p=x;
			x=y;
			y=p;
		}										//?x?????
		p=x;									//?????x??
		for(;y>=1;y=(y%2==0)?y/2:(y-1)/2){		//?y????y=1
			x=p;								//x???????????
			while(x>=1){						//?x>=1?
				x=(x%2==0)?x/2:(x-1)/2;			//??x?????
				if(x==y){						//????x=y
					cout<<x<<endl;				//?????
				    return 0;					//??
				}
			}
		}
	}
	return 0;
}