# include <bits/stdc++.h>
using namespace std;
const long long maxn = 1e6;
long long a[maxn],b[maxn],dp[maxn];
map <long long,long long> mp,ll;
long long last;
struct Segment{
    long long segm[maxn];
    void update(long long v, long long from, long long to, long long d, long long x)

    {


        if(from==to&&from==d)
        {
            segm[v] = max(segm[v],x);
            return ;
        }
        long long mid = (from+to)/2;
        if(d<=mid)update(2*v,from,mid,d,x);
        else
            update(2*v+1,mid+1,to,d,x);
        segm[v] = max(segm[2*v],segm[2*v+1]);
       // cout<<v<<"->>>"<<segm[v]<<endl;
    }
    long long query(long long v, long long from, long long to, long long l, long long r)
    {
        //cout<<v<<" "<<from<<" "<<to<<" "<<l<<" "<<r<<" "<<segm[v]<<endl;
        if(l>r)return 0;
        if(l<=from&&to<=r){//cout<<"RETURN: "<<segm[v]<<endl;
        return segm[v];}
        //;;cout<<"OPK"<<endl;
        long long mid = (from+to)/2;
        long long ans = 0;
        if(l<=mid)ans = query(2*v,from,mid,l,r);
        if(r>mid)ans=max(ans,query(2*v+1,mid+1,to,l,r));
        return ans;
    }
};
Segment S;
void solve()
{
    long long n;
    cin>>n;
    last = 0;
    long long i,j;
  mp.clear();
  ll.clear();
  memset(S.segm,0,sizeof(S.segm));
    for(i=1;i<=n;i++)
    {
        cin>>a[i];
        b[i] = a[i];
    }
   sort(b+1,b+n+1);
   long long prev=  -1;
   long long pos = 0;
   for(i=1;i<=n;i++)
   {
       if(b[i]!=prev)pos++;
       prev= b[i];
       mp[b[i]] = pos;
   }
   long long ans = 0;
   for(i=1;i<=n;i++)
   {
       long long tx= S.query(1,1,pos,1,mp[a[i]]-1);
       dp[i] = tx;
       //cout<<"**"<<tx<<endl;
      // cout<<i<<" "<<dp[i]<<endl;
       if(ll.find(a[i])!=ll.end())
       {
          // cout<<"upd"<<" "<<mp[a[i]]<<" "<<dp[ll[a[i]]]+1<<endl;
           S.update(1,1,pos,mp[a[i]],dp[ll[a[i]]]+1);
           ans = max(ans,dp[ll[a[i]]]+1);
       }
       ll[a[i]] = i;
   }
   cout<<2*ans<<endl;
}
int main()
{
ios_base::sync_with_stdio(false);
cin.tie(NULL);
cout.tie(NULL);
 freopen ("stairway.in","r",stdin); freopen ("stairway.out","w",stdout);
    long long n,m;
    long long i,j;
    long long t;
    cin>>t;
    while(t--)solve();
}