#include<iostream>
#include<cstdio>
#include<algorithm>
using namespace std;
int t,n;
const int N=3e5+10;
int a[N];
int f[N][5];
int pre[N][10];
int b[10];
int siz[N];
int main(){
	cin>>t;
	while(t--){
		int maxans=1;
		cin>>n;
		for(int i=1;i<=n;i++)scanf("%d",&a[i]);
		a[0]=-1;
		for(int i=1;i<=n;i++){
		int ff=0;
			for(int j=1;j<=5;j++){
				if(!b[j]&&ff)continue;
				if(!b[j])ff=1;
				int x=b[j];
				if(a[x]==a[i])continue;
				pre[i][++siz[i]]=x;
				for(int k=0;k<=siz[x];k++){
					if(a[pre[x][k]]==a[i])continue;
					f[i][siz[i]]=max(f[i][siz[i]],f[x][k]+1);
					maxans=max(maxans,f[i][siz[i]]);
					//cout<<i<<" "<<siz[i]<<" "<<f[i][siz[i]]<<endl; 
				}
			}
		int flag=0,f2=0,j=1;
		for(j=1;j<=5;j++){
		//	cout<<b[j]<<" ";
			 if(a[b[j]]==a[i])break;
		}
		//puts("") ;
		if(j<=5)b[j]=i;
		else b[1]=i;
		sort(b+1,b+1+5);
		}
		for(int i=0;i<=5;i++)b[i]=0;
		for(int i=0;i<=n;i++)
		for(int j=0;j<=5;j++)
		pre[i][j]=siz[i]=0;
		for(int i=0;i<=n;i++)
		for(int j=0;j<=5;j++)
		f[i][j]=0;
		cout<<maxans<<endl;
	}
}