#include <iostream>

#include <cstring>

#include <cstdio>

#include <algorithm>

#include <cmath>

using namespace std;

const int M=3044;

int n;

int s[M];

int f[M][M],mn[M][M],mx[M][M];

int sav[M],ans;

void init()

{

	memset(f,0,sizeof(f));

	int i,j,k;

	for(i=1;i<=n;i++)

	{

		sav[i]=i;

		f[i][i]=1;

		mn[i][i]=mx[i][i]=s[i];

	}

	for(i=1;i<=n;i++)

		for(j=i+1;j<=n;j++)

		{

			mx[i][j]=max(mx[i][j-1],s[j]);

			mn[i][j]=min(mn[i][j-1],s[j]);

		}

	for(i=2;i<=n;i++)

		for(j=1;j+i-1<=n;j++)

		{

			k=j+i-1;

			if(mx[j][k]-mn[j][k]+1!=k-j+1)

				f[j][k]=0;

			else

			{

				if(mn[j][k]<mn[j][sav[j]])

					f[j][k]=1;

				else

					f[j][k]=f[j][sav[j]]+f[sav[j]+1][k];

				sav[j]=k;

			}

		}

}

void solve()

{

	ans=max(1,f[1][n]);

	int i,j,k,t,tmp;

	//swap (i,j) , (t,k)

	for(i=1;i<=n;i++)

		for(j=i;j<=n;j++)

			if(f[i][j] && (i==1 || (f[1][i-1] && mn[1][i-1]==1)))	//be sure the first seg is start from 1 or the seg(i,j)

			{

				k=mx[i][j];

				if(k==n || (f[k+1][n] && mx[k+1][n]==n))

					for(t=j+1;t<=k;t++)

						if(mn[t][k]==i && f[t][k])

							ans=max(ans,f[1][i-1]+1/*seg[i][j]]*/+f[j+1][t-1]+1/*seg[t][k]*/+f[k+1][n]);

			}

}

int main()

{

	int T,i,j;

	cin>>T;

	while(T--)

	{

		scanf("%d",&n);

		for(i=1;i<=n;i++)

			scanf("%d",&s[i]);

		init();

		solve();

		cout<<ans<<endl;

	}

	return 0;

}