var a:char;
    f1,f2:text;
    ctcuv,ctlit,ctlitcon,i:longint;

begin

    assign(f1,'text.in');
    reset(f1);
    assign(f2,'text.out');
    rewrite(f2);
    ctcuv := 0;
    ctlit := 0;
    ctlitcon := 0;
    while not(eof(f1)) do
    begin
      read(f1, a);
      if (a in ['a'..'z', 'A'..'Z']) then inc(ctlitcon)
      else
        begin
          if (ctlitcon > 0) then inc(ctcuv);
          ctlit := ctlit + ctlitcon;
          ctlitcon := 0;
        end;
    end;

    if (ctlitcon > 0) then 
      begin 
        inc(ctcuv);
        ctlit := ctlit + ctlitcon;
      end;

    write(f2, ctlit div ctcuv);

        close(f1);
        close(f2);

end.