var c:char;
    lungime, nr, t:longint;
begin
assign(input,'text.in');
assign(output,'text.out');
reset(input);
rewrite(output);
 lungime:=0; nr:=0; t:=0;
 while not eof do
  begin
   read(c);
    if (not(c in ['a'..'z','A'..'Z'])) then inc(lungime)
                                      else if lungime>0 then
                                                         begin
                                                          inc(nr);
                                                          t:=t+lungime;
                                                         end;
           lungime:=0;
  end;
  writeln(t div nr);
close(input);
close(output);
end.