#include<stdio.h>
#include<stdlib.h>
int data[100][100] = {0};
int Dx[8] = {-1,1,-2,2,-2,2,-1,1};
int Dy[8] = {-2,-2,-1,-1,1,1,2,2};
int row,col;
int cun[100][2] = {0};
bool ret = false;
void DFS(int x,int y,int step);
int main()
{
int n;
//freopen("a.txt","r",stdin);
scanf("%d",&n);
for(int l = 0;l < n;l++)
{
ret = false;
scanf("%d",&row);
scanf("%d",&col);
printf("Scenario #%d:\n",l + 1);
data[0][0] = 1;
DFS(0,0,1);
data[0][0] = 0;
if(ret){
goto v;
}
if(ret == false){
printf("impossible\n\n");
continue;
}
v:for(int k = 0;k < row * col;k++)
{
printf("%c%d",cun[k][1] + 65,cun[k][0] + 1);
cun[k][0] = 0;
cun[k][1] = 0;
}
printf("\n\n");
}
return 0;
}
void DFS(int x,int y,int step)
{
if(step == row * col)
{
ret = true;
return;
}
for(int i = 0;i < 8;i++)
{
int Nx = x + Dx[i];
int Ny = y + Dy[i];
if(data[Nx][Ny] == 0 && Nx >= 0 && Nx < row && Ny >= 0 && Ny < col)
{
data[Nx][Ny] = 1;
cun[step][0] = Nx;
cun[step][1] = Ny;
DFS(Nx,Ny,step + 1);
data[Nx][Ny] = 0;
if(ret)
{
return;
}
cun[step][0] = 0;
cun[step][1] = 0;
}
}
}