program Project2;

{$APPTYPE CONSOLE}
var
f:text;
a:ansistring;
c,b:int64;
s:array[0..9] of boolean;
i:integer;

begin
assign(f, 'count.in');
reset(f);
readln(f, a);
c:=0;
b:=length(a);
repeat
inc(c);
case a[c] of
'0':s[0]:=true;
'1':s[1]:=true;
'2':s[2]:=true;
'3':s[3]:=true;
'4':s[4]:=true;
'5':s[5]:=true;
'6':s[6]:=true;
'7':s[7]:=true;
'8':s[8]:=true;
'9':s[9]:=true;
end;
until (b=c);
b:=0;
for i:=0  to 9 do
  if s[i] then inc(b);
assign(f, 'count.out');
rewrite(f);
writeln(f, b);
close(f);
end.