#include<bits/stdc++.h>
#define int long long
using namespace std;
void ts(){cout<<"IAKIOI\n";}
inline int read(){
	int n=0,f=1,ch=getchar();
	while(ch<'0'||ch>'9'){
		if(ch=='-')f=-1;
		ch=getchar();
	}
	while(ch>='0'&&ch<='9'){
		n=n*10+ch-'0';
		ch=getchar();
	}
	return n*f;
}
signed main(){
	int q=read();
	while(q--){
		int l=read(),r=read();
		if(l<=3&&3<=r){
			cout<<3<<"\n";continue;
		}
		bool f=0;
		for(int i=2;i<=30;i++){
			//ctz(x)=i.
			//ppc(x)=i.
			//l<=x*(1<<(i+1))+(1<<i)<=r
			if((1<<i)>r){continue;}
			int lb=(l+(1<<i)-1)/(1<<(i+1)),rb=(r-(1<<i))/(1<<(i+1));
			if((1<<(i-1))-1>rb){
				continue;
			}
			if(lb>((1<<(i-1))-1)){
				for(int j=30;j>=i-2;j--){
					//i-2 个.
					if((1<<j)+(1<<(i-2))-1<=rb){
						int v=(1<<j);
						int cc=i-2;
						for(int k=j-1;k>=0;k--){
							if(!cc)break;
							if(v+(1<<k)+(1<<(cc-1))-1<=rb){
								cc--,v+=(1<<k);
							}
						}
						if(v>=lb){
							cout<<v*(1<<(i+1))+(1<<i)<<"\n";
							f=1;break;
						}
						break;
					}
				}
				if(f)break;
			}
			else{
				cout<<(1<<i)+(1<<(i+1))*((1<<(i-1))-1)<<"\n";
				f=1;break;
			}
			//lb~rb 找 ppc=i-1 的.
		}
		if(!f)cout<<-1<<"\n";
	}
	return 0;
}
//look at my code
//my code is amazing