program ptext;
var f,g:text;
    a,b:integer;
    c:char;
    s,nr:longint;
begin
     assign(f,'text.in');
     assign(g,'text.out');
     reset(f);
     rewrite(g);
     a:=-1;
     b:=-1;
     s:=0;
     nr:=0;
     while (not eof(f)) do
           begin
                read(f,c);
                if((c>='a')and(c<='z')or(c>='A')and(c<='Z')) then
                                                                 if(a=-1) then
                                                                          begin
                                                                               a:=0;
                                                                               b:=0;
                                                                          end
                                                                 else inc(b)
                                                            else
                                                                begin
                                                                     if(a<>-1) then
                                                                               begin
                                                                                    inc(nr);
                                                                                    s:=s+(b-a+1);
                                                                               end;
                                                                a:=-1;
                                                                b:=-1;
                                                                end;
           end;
      if(a<>-1) then
                begin
                     inc(nr);
                     s:=s+(b-a+1);
                end;
     write(g,s div nr);
     close(f);
     close(g);
end.