type
  info=record
     fri:array[1..101]of integer;
     no:integer;
     count:integer;
  end;
label endof, endla;
var
  n,sum,i,j:integer;
  node:array[1..100]of info;
  temp:integer;
begin
assign(input,'input.txt');
assign(output,'output.txt');
  readln(input,n);
  for i:=1 to n do
    begin
      read(input,temp);
      j:=1;
      while temp<>0 do
         begin
            node[i].fri[j]:=temp;
            inc(j);
            read(input,temp);
         end;
      dec(j);
      node[i].count:=j;
      node[i].no:=0;
      if j=0 then goto endof;
      readln;
    end;
  sum:=0;
  node[1].no:=1;
  inc(sum);
  for i:=1 to node[1].count do
     node[node[1].fri[i]].no:=2;
  for i:=2 to n do
    begin
    if node[i].no<>2 then
       begin
         node[i].no:=1;
         inc(sum);
         for j:=1 to node[i].count do
            node[node[i].fri[j]].no:=2;
       end;
    end;
    writeln(output,sum);
    for i:=1 to n do
     begin
      if node[i].no=1 then
        begin
         write(output,i);
         write(output,' ');
        end;
     end;
     goto endla;
endof: write(output,0);
endla:  { TODO -oUser -cConsole Main : Insert code here }
end.