#include<fstream>
#include<iomanip>
#include<string.h>
#define Nmax 10002
using namespace std;
char s[Nmax],sconst[Nmax];
ifstream fin("perle.in");
ofstream fout("perle.out");
inline  void copy_a(char c[],const char wcopy[],int i) //l-am facut cred :-S
{char aux[Nmax],aux2[Nmax];
   memset(aux,0,sizeof(aux)); memset(aux2,0,sizeof(aux2));
	strncpy(aux,c,i);
   strcpy(aux2,c+i+1);
	memset(c,0,sizeof(c));
	strcpy(c,aux); strcat(c,wcopy); strcat(c,aux2);
}
void determen(char sconst[],char s[])
{int i;
	for(i=1;i<strlen(sconst);++i)
	   {switch(sconst[i])
	         {
	            case 'A': sconst[i]=s[i];break;
				case 'B': {if(s[i]=='2') copy_a(sconst,"2B",i);
						      else if(s[i]=='1')copy_a(sconst,"1A3AC",i);}break;
				case 'C': {if(s[i]=='2') sconst[i]='2';
						     else if(s[i]=='3') copy_a(sconst,"3BC",i);
							         else if(s[i]=='1') copy_a(sconst,"12A",i);}break;
            }
	   }
}
int perle_valid(char s[],int lg)
{
	if(lg==1) return 0;
	if(lg==2||lg==4) return -1;
	if(lg==3)
		if(s[0]=='1'&&s[1]=='2') return 0;
		   else return -1;
	if(lg==5)
		if(s[0]=='1'&&s[2]=='3'&&s[4]=='2') return 0;
		   else return -1;
    if(lg==6)
	   if(s[0]=='2'&&s[1]=='1'&&s[3]=='3'&&s[5]=='2') return 0;
	      else return -1;
    if(s[0]=='1') strcpy(sconst,"1A3AC");
	  else if(s[0]=='2') strcpy(sconst,"2B");
	          else  strcpy(sconst,"3BC");
    determen(sconst,s);  
 if(memcmp(s,sconst,sizeof(sconst))) return -1;
 return 0;
}
int main()
  {int n,i,j,lg;
	fin>>n;
	for(i=1;i<=n;++i)
	   {fin>>lg;
	    for(j=0;j<lg;++j) fin>>setiosflags(ios::skipws)>>s[j];
		fout<<(perle_valid(s,lg)+1)<<"\n"; memset(s,0,sizeof(s)); memset(sconst,0,sizeof(sconst));
		}
	return 0;
}