var f1,f2:text; n,n1:int64; a:array[1..10] of byte;
 c,i,j:integer; k:byte;
begin
 assign(f1,'count.in');
 reset(f1);
 readln(f1,n);
 close(f1);
 a[1]:=1;
 a[2]:=2;
 a[3]:=3;
 a[4]:=4;
 a[5]:=5;
 a[6]:=6;
 a[7]:=7;
 a[8]:=8;
 a[9]:=9;
 a[10]:=0;
 k:=0;
 if n=0 then
 k:=k+1;
 if n>36000 then
  begin
   n1:=n1 div 10000;
   n:=n mod 10000;
  end;

  while n<>0 do
   begin
     c:=n mod 10;
     n:=n div 10;
   for j:=1 to 10 do
    begin
      if c=a[j] then
     begin
      k:=k+1;
      a[j]:=25;
      end;
    end;
    end;
  while n1<>0 do
   begin
     c:=n1 mod 10;
     n1:=n1 div 10;
   for j:=1 to 10 do
    begin
      if c=a[j] then
     begin
      k:=k+1;
      a[j]:=25;
      end;
    end;
    end;
 assign(f2,'count.out');
 rewrite(f2);
 writeln(f2,k);
 close(f2);

end.