//
// Created by liuhao.
//
//      /##  /##             /##                               /######   /##   /##
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//     | ##  /##  /##   /## | #######    /######    /######  |__/  \ ## | ##  | ##
//     | ## | ## | ##  | ## | ##__  ##  |____  ##  /##__  ##   /######/ | ########
//     | ## | ## | ##  | ## | ##  \ ##   /####### | ##  \ ##  /##____/  |_____  ##
//     | ## | ## | ##  | ## | ##  | ##  /##__  ## | ##  | ## | ##             | ##
//     | ## | ## |  ######/ | ##  | ## |  ####### |  ######/ | ########       | ##
//     |__/ |__/  \______/  |__/  |__/  \_______/  \______/  |________/       |__/
#include<bits/stdc++.h>
#include<ext/pb_ds/assoc_container.hpp>
#include<ext/pb_ds/hash_policy.hpp>

using namespace __gnu_pbds;
using namespace std;
#define PII pair<int,int>
#define fi first
#define se second
#define int long long
#define endl '\n'
#define vii vector<vector<int>>

struct Fenwick {
	int n{};
	vector<int> tr;
	
	Fenwick(int n_) : n(n_), tr(n + 1) {}
	
	void add(int x, int y) {
		while (x <= n)tr[x] += y, x += x & -x;
	}
	
	int sum(int x) {
		int res = 0;
		while (x)res += tr[x], x -= x & -x;
		return res;
	}
};

auto CountColor(vector<int> &a, vector<pair<int, int>> &que) {
	int n = a.size();
	vector<int> ans(que.size());
	vector<vector<pair<int, int>>> f(n + 1);
	for (int i = 1; i < que.size(); i++)f[que[i].second].emplace_back(que[i].first, i);
	Fenwick arr(n + 1);
	map<int, int> mp;
	for (int i = 1; i <= n; i++) {
		if (mp[a[i]])arr.add(mp[a[i]], -1);
		mp[a[i]] = i;
		for (auto [l, j]: f[i])ans[j] = arr.sum(i) - arr.sum(l - 1);
	}
	return ans;
}

signed main() {
	ios::sync_with_stdio(0), cin.tie(0);
	int T;
	cin >> T;
	while (T--) {
		map<int, int> st;
		int n, m;
		cin >> n >> m;
		vector<int> a(n + 1);
		map<int, vector<int>> mp;
		for (int i = 1; i <= n; i++) {
			cin >> a[i];
			st[a[i]]++;
			if (!mp.count(a[i]))mp[a[i]].push_back(0);
			mp[a[i]].push_back(i);
		}
		map<int, int> b;
		Fenwick arr(n + 1);
		vector<PII > que(1);
		vector<int> ans1(1);
		for (auto &i: mp)i.se.push_back(n + 1);
		for (auto [k, val]: mp) {
			for (int i = 1; i < val.size(); i++) {
				if (val[i - 1] + 1 <= val[i] - 1)que.emplace_back(val[i - 1] + 1, val[i] - 1), ans1.emplace_back(k);
			}
		}
		que.emplace_back(1, n);
		int mex = 0;
		for (int i = 1; i <= m + 1; i++) {
			if (!st[i]) {
				mex = i;
				break;
			}
		}
		ans1.emplace_back(mex);
		auto ans2= CountColor(a,que);
		int ans = -1e18;
		for(int i=1;i<ans1.size();i++){
			ans=max(ans,ans2[i]-ans1[i]);
		}
		cout << ans << endl;
	}
	return 0;
}