#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()!.Split(' ', StringSplitOptions.RemoveEmptyEntries), 0);
    return T.Parse(_input[_iter++], null);
}
#endregion

static T[] Range<T>(int n, Func<T> F) => Enumerable.Range(0, n).Select(_ => F()).ToArray();

int Solve()
{
    var n = I<int>();
    var az = Range(n, I<int>);
    var bz = Range(n, I<int>);
    var uz = new List<int>();
    for (var i = 0; i < n; i++)
    {
        var a = az[i];
        var b = bz[i];
        uz.Add(Math.Max(a, b));
        uz.Add(Math.Min(a, b));
    }
    var mins = new List<int>();
    var iz = new int[uz.Count].AsSpan();
    iz.Fill(int.MaxValue);
    for (var i = 0; i < uz.Count; i++)
    {
        var v = uz[i];
        var j = mins.BinarySearch(v);
        if (j < 0) j = ~j;
        if (j == mins.Count) mins.Add(v);
        else mins[j] = v;
        iz[i] = j;
    }
    var res = 0;
    var pass = 0;
    var fail = mins.Count + 1;
    while (Math.Abs(fail - pass) >= 2)
    {
        var mid = (fail + pass) / 2;
        var lis1 = new int[mid];
        var next = mid - 1;
        for (var i = uz.Count - 1; i >= 0; i--)
        {
            if (iz[i] != next) continue;
            lis1[next--] = i;
        }
        var used = new HashSet<int>(lis1);
        var lis2 = new List<int>();
        for (var i = 0; i < uz.Count; i++) if (!used.Contains(i))
        {
            var v = uz[i];
            var j = ~lis2.BinarySearch(v);
            if (j < 0) continue;
            if (j == lis2.Count) lis2.Add(v);
            else lis2[j] = v;
        }
        res = Math.Max(res, mid + lis2.Count);
        if (lis2[^1] >= uz[lis1[^1]]) pass = mid;
        else fail = mid;
    }
    return res;
}

var ans = Range(I<int>(), Solve);
Console.WriteLine(string.Join(Environment.NewLine, ans));