#include <bits/stdc++.h>

using namespace std;

constexpr int MAXN = 5e5 + 10;
constexpr int MAXM = 5e5 + 10;

int n, m, a[MAXN], last[MAXM], tree[MAXN];
vector < pair < int, int > > query[MAXN];

void update(int pos, int val){
	if (pos == 0)return;
	for (;pos <= n; pos += pos & -pos){
		tree[pos] += val;
	}
}

int get(int pos){
	int sum = 0;
	for (;pos > 0; pos -= pos & -pos){
		sum += tree[pos];
	}
	return sum;
}

int get_range(int l, int r){
	if (l > r) return 0;
	return get(r) - get(l - 1);
}

signed main(){
	cin.tie(NULL)->sync_with_stdio(false);

	int test;
	cin >> test;

	while (test--){
		cin >> n >> m;

		for (int i = 1; i <= n; i ++){
			cin >> a[i];
		}

		for (int i = 1; i <= n; i ++){
			query[i - 1].emplace_back(last[a[i]] + 1, a[i]);
			last[a[i]] = i;
		}
		
		for (int i = 1; i <= n; i ++){
			last[a[i]] = n + 1;
		}

		for (int i = n; i >= 1; i --){
			query[last[a[i]] - 1].emplace_back(i + 1, a[i]);
			last[a[i]] = i;
		}

		for (int i = 1; i <= n; i ++){
			last[a[i]] = 0;
		}

		int ans = -1;

		for (int r = 1; r <= n; r ++){
			update(last[a[r]], -1);
			last[a[r]] = r;
			update(last[a[r]], 1);
			for (auto [l, v] : query[r]){
				ans = max(ans, get_range(l, r) - v);
			}
		}

		cout << ans << "\n";

		for (int i = 1; i <= n; i ++){
			last[a[i]] = 0;
			query[i].clear();
			tree[i] = 0;
		}
	}

	return (0 ^ 0);
}