#include <bits/stdc++.h>

using namespace std;

#define MAXN 500010

long long niz[MAXN];
bool obrisano[MAXN];
vector<long long> pozicije[MAXN];
long long bit[MAXN];
long long last_visit[MAXN];
vector<pair<pair<long long,long long>,long long>> query;

bool cmp(pair<pair<long long,long long>,long long> a,pair<pair<long long,long long>,long long> b)
{
    return (a.first.second<b.first.second);
}

void update(long long x,long long val,long long n)
{
    for (long long i=x;i<=n;i+=(i&(-i))) bit[i]+=val;
}

long long sol(long long x)
{
    long long br=0;
    for (long long i=x;i>=1;i-=(i&(-i))) br+=bit[i];
    return br;
}

void answer_queries(long long n)
{
    for (long long i=0;i<MAXN;i++) bit[i]=0;
    for (long long i=0;i<MAXN;i++) last_visit[i]=-1;
    long long query_container=0;
    long long ans[query.size()+10];
    for (long long i=0;i<n;i++)
    {
        if (last_visit[niz[i]]!=-1) update(last_visit[niz[i]]+1,-1,n);
        last_visit[niz[i]]=i;
        update(i+1,1,n);
        while (query_container<query.size() and query[query_container].first.second==i)
        {
            ans[query_container]=sol(query[query_container].first.second+1)-sol(query[query_container].first.first);
            query_container++;
        }
    }
    long long val=-LLONG_MAX;
    for (long long i=0;i<query.size();i++) val=max(val,ans[i]-query[i].second);
    cout<<val<<endl;
}

int main()
{
    long long t;cin>>t;
    for (long long z=0;z<t;z++)
    {
        long long n,m;cin>>n>>m;
        for (long long i=0;i<n;i++) cin>>niz[i];
        for (long long i=0;i<n;i++) obrisano[niz[i]]=false;
        vector<long long> vec;
        long long ans=-LLONG_MAX;
        for (long long i=0;i<n;i++)
        {
            if (obrisano[niz[i]]==false)
            {
                pozicije[niz[i]].clear();
                obrisano[niz[i]]=true;
                vec.push_back(niz[i]);
            }
            pozicije[niz[i]].push_back(i);
            if (pozicije[niz[i]].size()==1)
            {
                if (i-1<0) continue;
                query.push_back({{0,i-1},niz[i]});
            }
            else
            {
                long long siz=pozicije[niz[i]].size();
                long long poz1=pozicije[niz[i]][siz-2]+1;
                long long poz2=pozicije[niz[i]][siz-1]-1;
                if (poz2<poz1) continue;
                query.push_back({{poz1,poz2},niz[i]});
            }
        }
        sort(vec.begin(),vec.end());
        long long mex_niza=1;
        for (long long i=0;i<vec.size();i++)
        {
            if (mex_niza==vec[i]) mex_niza++;
            long long siz=pozicije[vec[i]].size();
            long long poz=pozicije[vec[i]][siz-1];
            if (n-1<poz+1) continue;
            query.push_back({{poz+1,n-1},vec[i]});
        }
        query.push_back({{0,n-1},mex_niza});
        sort(query.begin(),query.end(),cmp);
        //for (long long i=0;i<query.size();i++) cout<<query[i].first.first<<" "<<query[i].first.second<<" "<<query[i].second<<endl;
        answer_queries(n); query.clear();
    }
}