const inp = '1128.in';
      maxdat = 1000;
var   fname : text;
      dat   : array[1..maxdat,1..3] of integer;
      ndat  : array[1..maxdat] of byte;
      col   : array[1..maxdat] of byte;
      n,check,l,l2   : longint;
procedure out;
var loop,count,temp : longint;
 begin
      count:=0;
      for loop:=1 to n do
          if col[loop]=1 then inc(count);
      if count>n div 2 then temp:=2
      else temp:=1;
      if temp=1 then begin if count=n then begin writeln(1); writeln(1);
halt; end;
                           writeln(count)
                     end
      else if n-count>0 then writeln(n-count) else
           begin
                if count=n then begin writeln(1); writeln(1); halt; end;
                writeln(count);
           end;
      if n-count=0 then temp:=1;
      for loop:=1 to n do
          if col[loop]=temp then write(loop,' ');
      writeln;
      halt;
 end;
procedure process(now,ccc : longint);
var   loop,count,temp,gain : longint;
 begin
      col[now]:=ccc;
      for loop:=1 to ndat[now] do
          if col[dat[now,loop]]=0 then
             process(dat[now,loop],(ccc mod 2)+1);
 end;
procedure swap;
var l,l2,count : longint;
 begin
      for l:=1 to n do
          begin
               count:=0;
               for l2:=1 to ndat[l] do
                   if col[dat[l,l2]]=col[l] then inc(count);
               if count>1 then
                  begin
                       count:=0;
                       for l2:=1 to ndat[l] do
                           if col[dat[l,l2]]=(col[l] mod 2)+1 then inc(count);
                       if count>1 then begin writeln('NO SOLUTION'); halt; end
                       else col[l]:=(col[l] mod 2)+1;
                  end;
          end;
 end;
begin
     fillchar(ndat,sizeof(ndat),0);
     fillchar(col,sizeof(col),0);

     readln(n);
     for l:=1 to n do
         begin
              read(ndat[l]);
              for l2:=1 to ndat[l] do
                  read(dat[l,l2]);
              readln;
         end;

     if n=0 then begin writeln(0); halt; end;
     if n=2 then begin writeln(1); writeln(1); halt; end;
     check:=0;
     for l:=1 to n do
         if col[l]=0 then
            process(l,1);
     swap;
     out;
end.