The only difference between easy and hard versions is constraints.

You are given a sequence a consisting of n positive integers.

Let's define a three blocks palindrome as the sequence, consisting of at most two distinct elements (let these elements are a and b, a can be equal b) and is as follows: [\underbrace{a, a, ..., a}_{x}, \underbrace{b, b, ..., b}_{y}, \underbrace{a, a, ..., a}_{x}]. There x, y are integers greater than or equal to 0. For example, sequences [], [2], [1, 1], [1, 2, 1], [1, 2, 2, 1] and [1, 1, 2, 1, 1] are three block palindromes but [1, 2, 3, 2, 1], [1, 2, 1, 2, 1] and [1, 2] are not.

Your task is to choose the maximum by length subsequence of a that is a three blocks palindrome.

You have to answer t independent test cases.

Recall that the sequence t is a a subsequence of the sequence s if t can be derived from s by removing zero or more elements without changing the order of the remaining elements. For example, if s=[1, 2, 1, 3, 1, 2, 1], then possible subsequences are: [1, 1, 1, 1], [3] and [1, 2, 1, 3, 1, 2, 1], but not [3, 2, 3] and [1, 1, 1, 1, 2].

Input

The first line of the input contains one integer t (1 ≤ t ≤ 2000) — the number of test cases. Then t test cases follow.

The first line of the test case contains one integer n (1 ≤ n ≤ 2000) — the length of a. The second line of the test case contains n integers a_1, a_2, ..., a_n (1 ≤ a_i ≤ 26), where a_i is the i-th element of a. Note that the maximum value of a_i can be up to 26.

It is guaranteed that the sum of n over all test cases does not exceed 2000 (∑ n ≤ 2000).

Output

For each test case, print the answer — the maximum possible length of some subsequence of a that is a three blocks palindrome.

Example

Input


6
8
1 1 2 2 3 2 1 1
3
1 3 3
4
1 10 10 1
1
26
2
2 1
3
1 1 1


Output


7
2
4
1
1
3
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.util.*;

public class Practice {
	public static long mod = (long) Math.pow(10, 9) + 7;
	public static long mod2 = 998244353;
	public static int tt = 1;
	public static ArrayList<Integer> prime;

	public static void main(String[] args) throws Exception {
		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
		PrintWriter pw = new PrintWriter(System.out);
		int t = Integer.parseInt(br.readLine());
		while (t-- > 0) {
			int n = Integer.parseInt(br.readLine());
			int[] arr = new int[n];
			String str = (br.readLine());
			String[] s1 = str.split(" ");
			for (int i = 0; i < n; i++) {
				arr[i] = Integer.parseInt(s1[i]);
			}
			System.out.println(getAns(n, arr));
		}

		pw.close();
	}

	private static int getAns(int n, int[] arr) {
		// TODO Auto-generated method stub
		int ans = 0;
		int[] fre = new int[27];
		for (int i = 0; i < n; i++) {
			fre[arr[i]]++;
		}
		for (int i = 0; i < 27; i++) {
			ans = Math.max(ans, fre[i]);
		}
		for (int i = 1; i <= 27; i++) {
			int[] ff = new int[27];
			for (int j = 0; j < 27; j++) {
				ff[j] = fre[j];
			}
			int curr = 0;
			int l = 0, r = n - 1;
			while (l < r) {
				if (arr[l] == i) {
					ff[arr[l]]--;
					while (r > l && arr[r] != i) {
						ff[arr[r]]--;
						r--;
					}
					if (r == l) {
						break;
					}
					ff[arr[r]]--;
					r--;
					l++;
					curr += 2;
					int pre = 0;
					for (int j = 0; j < 27; j++) {
						pre = Math.max(ff[j], pre);
					}
					pre += curr;
					ans = Math.max(pre, ans);
				} else {
					ff[arr[l]]--;
					l++;
				}
			}

		}
		return ans;
	}

}

//	private static void getFac(long n, PrintWriter pw) {
//		// TODO Auto-generated method stub
//		int a = 0;
//		while (n % 2 == 0) {
//			a++;
//			n = n / 2;
//		}
//		if (n == 1) {
//			a--;
//		}
//		for (int i = 3; i <= Math.sqrt(n); i += 2) {
//			while (n % i == 0) {
//				n = n / i;
//				a++;
//			}
//		}
//		if (n > 1) {
//			a++;
//		}
//		if (a % 2 == 0) {
//			pw.println("Bob");
//		} else {
//			pw.println("Alice");
//		}
//		//System.out.println(a);
//		return;
//	}

//	private static long power(long a, long p) {
//		// TODO Auto-generated method stub
//		long res = 1;
//		while (p > 0) {
//			if (p % 2 == 1) {
//				res = (res * a) % mod;
//			}
//			p = p / 2;
//			a = (a * a) % mod;
//		}
//		return res;
//	}
//
//	private static void fac() {
//		fac[0] = 1;
//		// TODO Auto-generated method stub
//		for (int i = 1; i < fac.length; i++) {
//			if (i == 1) {
//				fac[i] = 1;
//			} else {
//				fac[i] = i * fac[i - 1];
//			}
//			if (fac[i] > mod) {
//				fac[i] = fac[i] % mod;
//			}
//		}
//	}
//
//	private static int getLower(Long long1, Long[] st) {
//		// TODO Auto-generated method stub
//		int left = 0, right = st.length - 1;
//		int ans = -1;
//		while (left <= right) {
//			int mid = (left + right) / 2;
//			if (st[mid] <= long1) {
//				ans = mid;
//				left = mid + 1;
//			} else {
//				right = mid - 1;
//			}
//		}
//		return ans;
//	}

//	private static long getGCD(long l, long m) {
//
//		long t1 = Math.min(l, m);
//		long t2 = Math.max(l, m);
//		while (true) {
//			long temp = t2 % t1;
//			if (temp == 0) {
//				return t1;
//			}
//			t2 = t1;
//			t1 = temp;
//		}
//	}