#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define rep(i, n) for (int i = 0; i < (int)(n); i++)
template<typename T> bool chmin(T& a, T b){if(a > b){a = b; return true;} return false;}
template<typename T> bool chmax(T& a, T b){if(a < b){a = b; return true;} return false;}
const long long mod=998244353;
const long long mod2=469762049;
void solve(){
    ll N,M;cin>>N>>M;
    ll l=0,r=2e14;
    while(l!=r){
        ll m1=(l*2+r)/3,m2=(l+r*2)/3;
        if(m2*2>N) r=m1;
        ll cnt1=min((N-2*m1)/4,(M+4*m1)/2);
        ll cnt2=min((N-2*m2)/4,(M+4*m2)/2);
        if(cnt1<cnt2) l=m1+1;
        else r=m2;
    }
    ll ans=min((N-2*l)/4,(M+4*l)/2)*3;
    cout<<ans<<"\n";
}
int main(){
    cout.tie()->sync_with_stdio(0);
    cin.tie(0);
    int T;cin>>T;
    while(T--) solve();
}