var m,n,i,j:byte;
    s:string;
pole:array[1..55]of string;
begin
readln(n);
while n<>0 do
 if n=1 then  begin writeln('Sheet 1, front: Blank, 1');writeln;readln(n);end else

  begin
    for i:=1 to n do 
      begin str(i,s); pole[i]:=s;end;
    for i:=(n+1) to (n+5) do pole[i]:='Blank';
    m:= (n+(n mod 4));
    if n mod 4 = 0 then j:=n;
    if n mod 4 = 3 then j:=n+1;
    if n mod 4 = 2 then j:=n+2;
    if n mod 4 = 1 then j:=n+1; 
    for i:=1 to (m div 2) do     
      begin
        if i mod 2 = 0 then  
        writeln('Sheet ',(((i-1) div 2)+1),', back : ',pole[0+i],', ',pole[m+1-i])  
        else
	writeln('Sheet ',(((i-1) div 2)+1),', front: ',pole[m+1-i],', ',pole[0+i]);  
      end;
      writeln;
     readln(n); 
  end;
end.