program Text_1;
const
   abc : string = ('abcdefghjiklmnopqrstuvwxyzABCDEFGHJIKLMNOPQRSTUVWXYZ');
var
   fl : text;
   s : string;
   c : char;
   n1, n2, n, k, i : integer;

function cuvint(s1:string):boolean;
begin
   cuvint := false;
   for i := 1 to length(s1) do
      if pos(s1[i],abc) = 0 then
         exit;
   cuvint := true;
end;
begin
   assign(fl,'text.in');
   reset(fl);
   n1 := 0;
   n2 := 0;
   s := '';
   while not eof(Fl) do
      begin
         read(fl,c);
         if (c = ' ') or (c = '!') or (c='.') or (c='?') or (c=',') or (c='-') then
            begin
               if (cuvint(s)) and (s <> '') then
                  begin
                     n1 := n1 + length(s);
                     n2 := n2 + 1;
                  end;
               s := '';
            end
         else
           s := s + c;
      end;
   close(fl);
   assign(fl,'text.out');
   rewrite(fl);
   writeln(fl,n1 div n2);
   close(fl);
end.