#include<bits/stdc++.h>
#define ll long long
#define int long long
#define mod 998244353
using namespace std;
ll o[500010],n,m;
inline ll lowbit(ll x)
{
    return x&(-x);
}
void change(ll k,ll x)
{
    for(int i=k;i<=n;i+=lowbit(i))o[i]+=x;
}
ll query(ll k)
{
    ll res=0;
    for(int i=k;i>=1;i-=lowbit(i))res+=o[i];
    return res;
}
ll a[500010],last[500010];
struct qu
{
    ll l,r,mex;
};
vector<qu>b[500010];
void work()
{
    ll ans=0;
    cin>>n>>m;
    for(int i=1;i<=n;i++)b[i].clear();
    for(int i=1;i<=n;i++)
    {
        cin>>a[i];
        b[i-1].push_back({last[a[i]]+1,i-1,a[i]});
        last[a[i]]=i;
    }
    for(int i=1;i<=n+1;i++)
    {
        b[n].push_back({last[i]+1,n,i});
        if(last[i]==0)break;
    }
    for(int i=1;i<=n;i++)last[a[i]]=0;
    for(int i=1;i<=n;i++)
    {
        if(last[a[i]]!=0)change(last[a[i]],-1);
        change(i,1);
        last[a[i]]=i;
        for(auto x:b[i])
        {
            ll l=x.l,r=x.r,mex=x.mex;
           if(r>=l)ans=max(ans,query(r)-query(l-1)-mex);
        }
    }
    for(int i=1;i<=n;i++)
    {
        last[a[i]]=0;
        o[i]=0;
    }
    cout<<ans<<'\n';
}
signed main()
{
    ios::sync_with_stdio(0);cin.tie(0);cout.tie(0);
    int T=1;
    cin>>T;
    while(T--)
    {
        work();
    }
}