#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
typedef long double ld;
typedef pair<int,int> PII;
typedef pair<ll,ll> PLL;
#define endl '\n'
#define debug(x) cout<<#x<<": "<<x<<endl
#define lowbit(x) (x&-x)
#define gcd __gcd
#define i128 __int128
#define rep(i, a, b) for(ll i = (a); i <= (b); i++)
#define per(i, a, b) for(ll i = (a); i >= (b); i--)
const int N=5e5+10,M=1e3+10;
const ll mod=1e9+7;
const ld eps=1e-12;
const double pi=acos(-1.0);
const double pi1=pi/180,pi2=180/pi;
mt19937_64 rnd(chrono::steady_clock::now().time_since_epoch().count());
//unordered_map<int,int>mp;
#define poly vector<int>

int tree[N];
int query(int k)
{
    int ans=0;
    for(int i=k;i>0;i-=lowbit(i)) ans+=tree[i];
    return ans;
}

void add(int x,int k)
{
    if(x==0) return;
    for(int i=x;i<N;i+=lowbit(i)) tree[i]+=k;
}

vector<int>pos[N];

void solve()
{
    int n,m;
    cin>>n>>m;
    int a[n+1];
    set<int>st;
    for(int i=1;i<=n;i++)
    {
        cin>>a[i];
        st.insert(a[i]);
        pos[a[i]].push_back(i);
    }
    vector<array<int,3>>path;
    for(auto mex:st)
    {
        int last=1;
        for(auto p:pos[mex])
        {
            if(p-1>=last) path.push_back({p-1,last,mex});
            last=p+1;
        }
        int p=n+1;
        if(p-1>=last) path.push_back({p-1,last,mex});
    }
    sort(path.begin(),path.end());
    int now=0;//处理完了哪个数
    map<int,int>mp;
    int ans=-1e9;
    for(auto [r,l,mex]:path)
    {
        while(now<r)
        {
            now++;
            if(mp.count(a[now])) add(mp[a[now]],-1);
            add(now,1);
            mp[a[now]]=now;
        }
        ans=max(ans,query(r)-query(l-1)-mex);
    }
    for(int i=1;i<=n+1;i++)
    {
        if(!mp.count(i))
        {
            ans=max(ans,(int)mp.size()-i);
            break;
        }
    }
    for(auto [x,y]:mp)
    {
        add(y,-1);
    }
    for(auto p:st) pos[p].clear();
    cout<<ans<<endl;
}

int main()
{
	ios::sync_with_stdio(0);
	cin.tie(0),cout.tie(0);
	
	int T=1;
	cin>>T;
	
	while(T--)
	{
		solve();
	}
	return 0;
}