#include<bits/stdc++.h>
#define int long long
#define endl '\n'
#define lowbit(x) (x&(-x))
using namespace std;
const int MAXN=5e5+5;
int n,m,num=0;
int a[MAXN],cnt[MAXN],belong[MAXN];
struct node{
    int l,r;
    bool operator <(node b)const{return belong[l]^belong[b.l]?belong[l]<belong[b.l]: (belong[l]&1)?r<b.r:r>b.r;}
};
struct Fenwick{
    int n;
    vector<int> tr;
    Fenwick(int n):n(n),tr(n){}
    void modify(int x,int c){
        for(int i=x+1;i<=n;i+=lowbit(i)) tr[i-1]+=c;
    }
    int query(int x){
        int res=0;
        for(int i=min(x+1,n);i;i-=lowbit(i)) res+=tr[i-1];
        return res;
    }
};
void solve()
{
    cin>>n>>m;
    vector<int> X;
    for(int i=1;i<=n;i++) 
    {
        cin>>a[i];
        X.push_back(a[i]);
        X.push_back(a[i]+1);
    }
    X.push_back(1);
    sort(X.begin(),X.end());
    X.erase(unique(X.begin(),X.end()),X.end());
    int siz=X.size();
    vector<vector<int>> pos(siz+1);
    for(int i=1;i<=n;i++)
    {
        a[i]=lower_bound(X.begin(),X.end(),a[i])-X.begin()+1;
        pos[a[i]].push_back(i);
    }
    vector<node> q(1);
    for(int i=1;i<=siz;i++)
    {
        if(pos[i].size())
        {
            if(pos[i][0]-1>=1) q.push_back({1,pos[i][0]-1});
            if(pos[i].back()+1<=n) q.push_back({pos[i].back()+1,n});
        }
        if(pos[i].size()>=2)
        {
            for(int j=0;j<pos[i].size()-1;j++)
                if(pos[i][j]+1<=pos[i][j+1]-1)
                    q.push_back({pos[i][j]+1,pos[i][j+1]-1});
        }
    }
    q.push_back({1,n});
    int t=sqrt((int)q.size());
    for(int i=1;i<q.size();i++)
        belong[i]=i/t+1;
    sort(q.begin()+1,q.end());


    Fenwick tr(siz+1);
    auto add=[&](int x)
    {
        cnt[a[x]]++;
        if(cnt[a[x]]==1)
        {
            num++;
            tr.modify(a[x],1);
        }
    };
    auto del=[&](int x)
    {
        cnt[a[x]]--;
        if(!cnt[a[x]]) 
        {
            num--;
            tr.modify(a[x],-1);
        }
    };
    auto getmin=[&]()
    {
        int T=sqrt(siz)+1,pos=0;
        for(int i=T;i>=0;i--)
        {
            int tmp=pos+(1<<i);
            if(tmp>siz) continue;
            if(tr.query(tmp)!=tmp) continue;
            pos=tmp;
        }
        return pos;
    };
    int L=1,R=0,ans=-1;
    for(int i=1;i<q.size();i++)
    {
        auto [l,r]=q[i];
        while(R<r) add(++R);
        while(L>l) add(--L);
        while(R>r) del(R--);
        while(L<l) del(L++);
        int minn=getmin()+1;
        ans=max(ans,num-minn);
    }
    cout<<ans<<endl;
}
signed main()
{
    cin.tie(0)->sync_with_stdio(0);
    int t=1;cin>>t;
    while(t--) solve();
    return 0;
}