#include <iostream>

 #include<cstdio>

 #include<cstring>

 #include<cstdlib>

 #include<stack>

 #include<queue>

 #include<iomanip>

 #include<cmath>

 #include<map>

 #include<vector>

 #include<algorithm>

 using namespace std;

 struct node

 {

     int x,y;

 }q[]; //记录路径

 int p,c;

 int vis[][];

 int d[][]={{-,-},{,-},{-,-},{,-},{-,},{,},{-,},{,}};//顺序很重要，不能改变

 int dfs(int i,int j,int step)

 {

     vis[i][j]=;

     q[step].x=i;

     q[step].y=j;

     if(step==p*c) return ;

     for(int k=; k<; k++)

     {

         int a=i+d[k][];

         int b=j+d[k][];

         if(!vis[a][b]&&a>=&&a<=p&&b>=&&b<=c)

         if(dfs(a,b,step+))

         return ;

     }

     vis[i][j]=;

     return ;

 }

 int main()

 {

     int t,i;

     cin>>t;

     for(i=; i<=t; i++)

     {

         memset(vis,,sizeof(vis));

         cin>>p>>c;

         printf("Scenario #%d:\n",i);

         if(dfs(,,))

         {

             for(int j=; j<=p*c; j++)

             printf("%c%d",q[j].y+,q[j].x);

             cout<<endl<<endl;

         }

         else

         cout<<"impossible"<<endl<<endl;

     }

     return ;

 }