//
// Created by liuhao.
//
//      /##  /##             /##                               /######   /##   /##
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//     | ##  /##  /##   /## | #######    /######    /######  |__/  \ ## | ##  | ##
//     | ## | ## | ##  | ## | ##__  ##  |____  ##  /##__  ##   /######/ | ########
//     | ## | ## | ##  | ## | ##  \ ##   /####### | ##  \ ##  /##____/  |_____  ##
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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;
	}
	int operator[](int x) {
		return sum(x) - sum(x - 1);
	}
	int operator()(int l, int r) {
		return sum(r) - sum(l - 1);
	}
};
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;
		vector<int>ans1;
		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);
		vector<vector<PII>>f(n+1);
		for(int i=0;i<que.size();i++) {
			auto [l,r]=que[i];
			f[r].push_back({l, i});
		}
		for(int i=1;i<=n;i++){
			if(b[a[i]]){
				arr.add(b[a[i]],-1);
			}
			arr.add(i,1);
			b[a[i]]=i;
			for(auto [l,j]:f[i]){
				ans1[j]=arr.sum(i)-arr.sum(l-1)-ans1[j];
			}
		}
		int ans=0;
		for(auto i:ans1)ans=max(ans,i);
		cout<<ans<<endl;
	}
    return 0;
}