const fi = '';
          fo = '';
          maxn = 500;
    var n:longint;
        a: array[1..maxn,1..maxn] of boolean;
        l,r: array[1..maxn] of longint;
    procedure enter;
    var i,j,k,p:longint;
    begin
      readln(n);
      for i:=1 to n do
      begin
        for j:=1 to n do
        begin
          read(p);
          a[i,j]:=(p=1);
          if a[i,j] then inc(l[i]);
        end;
        readln;
      end;
      for i:=1 to n do
      for j:=1 to n do
      for k:=1 to n do
      if not a[i,j] and a[i,k] and a[k,j] then
      begin
        a[i,j]:=true;
        inc(l[i]);
      end;
    end;
    procedure solve;
    var i,j:longint;
        res:longint;
    begin
      res:=0;
      for i:=1 to n do
      if l[i]=n then
      begin
        inc(res);
        r[res]:=i;
      end;
      writeln(res);
      for i:=1 to res do
      writeln(r[i]);
    end;
    begin
      assign(input,fi);
      reset(input);
      assign(output,fo);
      rewrite(output);
      enter;
      solve;
      close(input);
      close(output);
    end.