uses crt;
   var s:string; i, k1,k2:byte;
begin clrscr;
      readln(s);
      for i:=1 to length(s) do
      if s[i] in ['A'..'Z','a'..'z'] then inc(k1);
      i:=1;
      while i<=length(s) do begin
       if s[i] in ['A'..'Z','a'..'z'] then begin
        while s[i] in ['A'..'Z','a'..'z'] do inc(i);
        inc(k2);
        end; inc(i);  end;
       writeln('Lungimea medie:',k1 div k2);
       readln;
      end.