#include<iostream>
#include <cstring>
#include <string>
using namespace std;
bool board[27][27],is_find;
int p,q,T;
int dir[8][2]={{-2,-1},{-2,1},{-1,-2},{-1,2},{1,-2},{1,2},{2,-1},{2,1}};
string ans;
bool DFS(int i,int j,int step)
{
	if(i<=0 || j<=0 || i>p || j>q || board[i][j]) return false;
	board[i][j]=true;
	if(step==p*q-1) return true;
	for(int k=0;k<8;++k)
	{	
		int di=i+dir[k][1];
		int dj=j+dir[k][0];
		if(DFS(di,dj,step+1))
		{
			ans.insert(0,1,di+'0');
			ans.insert(0,1,dj+'A'-1);
			return true;
		}
	}
	board[i][j]=false;
	return false;
}
int main()
{
	cin>>T;
	for(int s=1;s<=T;++s)
	{
		cin>>p>>q;
		ans.clear();
		is_find=false;
		for(int i=1;i<=p && !is_find;++i)
		{
			for(int j=1;j<=q;++j)
			{
				memset(board,false,sizeof(board));
				if(DFS(i,j,0)){ ans.insert(0,1,i+'0');ans.insert(0,1,j+'A'-1);is_find=true;break;}
			}
		}
		cout<<"Scenario #"<<s<<":"<<endl;
		if(ans.empty())cout<<"impossible"<<endl<<endl;
		else cout<<ans<<endl<<endl;
	}
	return 0;
}