#include <bits/stdc++.h>
using namespace std;
const int nmax = 1e4;

int tg[nmax+5];
int n;

string fin;
int poz;
bool eval() {
	bool ok = true;
	while(ok and poz<n) {
		ok = false;
		if(fin[poz]>='1' and fin[poz]<='3') {
			ok = true;
		}
		else if(fin[poz]=='A') {
			fin[poz] = tg[poz] + '0';
			ok = true;
		}
		else if(fin[poz]=='B') {
			if(tg[poz]==2) {
				fin.replace(poz,1,"2B");
				ok = true;
			}
			else if(tg[poz]==1) {
				fin.replace(poz,1,"1A3AC");
				ok = true;
			}
		}
		else if(fin[poz]=='C') {
			if(tg[poz]==2) {
				fin[poz] = '2';
				ok = true;
			}
			else if(tg[poz]==3) {
				fin.replace(poz,1,"3BC");
				ok = true;
			}
			else if(tg[poz]==1) {
				fin.replace(poz,1,"12A");
				ok = true;
			} 
		}
		poz++;
	}
	if(fin.size()>n) return false;
	for(int i=0; i<n; i++) 
		if(tg[i]+'0'!=fin[i]) return false;
	return true;
}

int main() {
	ifstream f("perle.in");
	ofstream g("perle.out");
	
	int q; f >> q;
	for(int cas=1; cas<=q; cas++) {
		f >> n;
		for(int i=0; i<n; i++) f >> tg[i];
		fin = "";
		if(n==1) fin = fin + "A";
		else if(tg[0]==1 and n==3) fin = fin + "C";
		else if(tg[0]==1) fin = fin + "B";
		else if(tg[0]==2) fin = fin + "B";
		else if(tg[0]==3) fin = fin + "C";
		poz = 0; g << eval() << "\n";
	}
	return 0;
}