var f:text; s:char; lungime,nrcuv:integer;
    a,b:set of char;
    cuvint:string;
begin
nrcuv:=0;
a:=['a'..'z'];
b:=['A'..'Z'];
Assign(f,'text.in');
reset(f);
While not eof(f) do
begin
 While not eoln(f) do
  begin
   cuvint:='';
   read(f,s);
   While (s in a)or(s in b)  do
    begin
     read(f,s);
     cuvint:=cuvint+s;
    end;
   if cuvint<>'' then nrcuv:=nrcuv+1;
   lungime:=lungime+length(cuvint);
  end;
 readln(f);
end;
Close(f);
Assign(f,'text.out') ;
rewrite(f);
Writeln(f,trunc(lungime/nrcuv));
Close(f);


end.