#include <bits/stdc++.h>
using namespace std;

int solve() {
	int N; cin >> N;
	vector<int> P(N);
	for (int i = 0; i < N; i++) {
		cin >> P[i]; P[i]--;
	}

	vector<int> ans(N);
	vector<array<int, 2>> stuff(N, {-1, -1});
	auto update = [&](array<int, 2>& a, int v) -> void {
		if (a[0] < v) {
			swap(a[0], a[1]);
			a[0] = v;
		} else if (a[1] < v) {
			a[1] = v;
		}
	};
	for (int i = N-1; i >= 0; i--) {
		ans[i] = max({1, stuff[i][0], stuff[i][1]+1});
		if (i > 0) {
			int p = P[i];
			update(stuff[p], ans[i]);
		}
	}
	return ans[0];
}

int main() {
	ios_base::sync_with_stdio(false), cin.tie(nullptr);

	int T; cin >> T;
	while (T--) {
		cout << solve() << '\n';
	}
}