#include <bits/stdc++.h>

using namespace std;
using ll = long long;
using i128 = __int128;
using pll = pair<ll, ll>;
using vll = vector<ll>;
template <class T>
using max_heap = priority_queue<T>;
template <class T>
using min_heap = priority_queue<T, vector<T>, greater<>>;

constexpr ll INF = (1LL << 60);
ll ALPHABET_N = 26;
#define rep(i, n) for (ll i = (ll)0; i < (ll)n; i++)
#define rep_(i, k, n) for (ll i = (ll)k; i < (ll)n; i++)
#define rrep(i, n) for (ll i = (ll)(n) - 1; i >= 0; i--)
#define all(a) a.begin(), a.end()
#define sum_(a) accumulate(a.begin(), a.end(), 0LL)

template <class T>
bool chmax(T &a, const T &b)
{
    if (a < b)
    {
        a = b;
        return true;
    }
    return false;
}

template <class T>
bool chmin(T &a, const T &b)
{
    if (a > b)
    {
        a = b;
        return true;
    }
    return false;
}

#include <atcoder/all>
using namespace atcoder;
using mint = modint998244353;

int main()
{
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    ll t;
    cin>>t;
    rep(_, t) {
        ll n, m;
        cin>>n>>m;
        if(n % 2 == 1) n--;
        if(m % 2 == 1) m--;
        ll cnt = min(n / 4, m / 2);
        n -= cnt * 4;
        m -= cnt * 2;
        ll ans = cnt;
        if(n > 0) {
            ll l = 0, r = n + 1;
            while(r - l > 1) {
                ll mid = (l + r) / 2;
                ll usen = mid * 4;
                ll n_ = n - usen;
                ll m_ = m + (n_ / 2 * 4);
                m_ = m_ - mid * 2;
                if(n_ >= 0 && m_ >= 0) {
                    l = mid;
                } else {
                    r = mid;
                }
            }
            ans += l;
        }
        cout<<ans * 3<<endl;
    }
    return 0;
}