program cret1;
var i,sum,j,c,c2:integer;
    ma:real;
    s,s1:string;
    f,g:text;
    ok:boolean;
begin
 assign(f,'text.in');
 reset (f);
 assign(g,'text.out');
 rewrite (g);
 read (f,s);
 i:=1; c2:=0; sum:=0; c:=0; j:=1;
 s1:='abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ';
 while i<=length(s) do
   begin
   j:=1;   ok:=false;
    while j<=length(s1) do
    begin
    if s[i]=s1[j]  then
     begin
      sum:=sum+1;
      c2:=0;
      ok:=true;
      break;
     end
      else
     j:=j+1;
    end;
    if ok=false then
     begin
     if c2=0 then
      c:=c+1;
      c2:=c2+1;
      end;
    i:=i+1;
   end;
  if c2=0 then
   c:=c+1;
 ma:=sum/c;
 write (g,ma:0:0);
 close (f);
 close (g);
end.