Const


 Value: Array [0..5,0..5] of LongInt =


(


(0,0,    0,    0,   0,   0),


(0,32768,16384,8192,4096,0),


(0,2048 ,1024 ,512 ,256 ,0),


(0,128  ,64   ,32  ,16  ,0),


(0,8    ,4    ,2   ,1   ,0),


(0,0,    0,    0,   0,   0)


);




Var


 Res,N,xx,yy,Y,Start,X: LongInt;


 S: String;


 Mask: Array [1..3,1..3] of LongInt;


 Masks: Array [1..16] of LongInt;




Function Good(X: LongInt): Boolean;


Var Num,N: LongInt;


begin


 Num:=Start;


 For N:=1 to 16 do


  If (X and (1 shl (N-1))<>0) then


   Num:=Num xor Masks[N];


 Good:=(Num=0) or (Num=65536);


end;




Function NBits(X: LongInt): LongInt;


Var Res,N: LongInt;


begin


 Res:=0;


 N:=X;


 While N>0 do


  begin


   Inc(Res, N and 1);


   N:=N shr 1;


  end;


 NBits:=Res;


end;




begin


 Start:=0;


 For Y:=1 to 4 do


  begin


   ReadLn(S);


   For X:=1 to 4 do


    If S[X]='B' then


     Start:=Start or Value[Y,X];


  end;




 For Y:=1 to 3 do


  begin


   ReadLn(S);


   For X:=1 to 3 do


    If s[X]='0' then


     Mask[y,x]:=0


    else


     Mask[y,x]:=1;


  end;




 For YY:=1 to 4 do


  for XX:=1 to 4 do


   begin


    N:=0;


    For X:=-1 to 1 do


     For Y:=-1 to 1 do


      N:=N + (Mask[Y+2,x+2] * Value[yy+y,xx+x]);


    Masks[yy*4-4+xx]:=N;


   end;




 Res:=-1;


 For X:=0 to 65536 do


  If ((Res=-1) or (NBits(X)<Res)) and (Good(X)) then


   Res:=NBits(X);




 If Res<>-1 then


  WriteLn(res)


 else


  WriteLn('Impossible');


end.