#nullable enable

#region
var (_input, _iter) = (Array.Empty<string>(), 0);
T I<T>() where T : IParsable<T>
{
    while (_iter >= _input.Length) (_input, _iter) = (Console.ReadLine()!.Trim().Split(' '), 0);
    return T.Parse(_input[_iter++], null);
}
#endregion

long Solve(long n, long m)
{
    if (m == 0)
    {
        if (n <= 2) return 0;
        if (n <= 4) return 3; 
        return n / 5 * 6 + Solve(n % 5, 0);
    }
    var u = Math.Min(n / 2, m);
    if (u == 0) return 0;
    return Solve(n - u * 2, m - u) + u * 3;
}

var t = I<int>();
var ans = new List<long>();
for (var i = 0; i < t; i++)
{
    var n = I<int>();
    var m = I<int>();
    ans.Add(Solve(n / 2, m / 2));
}
Console.WriteLine(string.Join(Environment.NewLine, ans));