var  a,k,b,i:integer;
begin
writeln ('Ââåäèòå ÷èñëî a');
readln(a);
i:=0;
k:=0;
while a>0 do begin
b:=a;
 while ( b<>0 ) do
 begin
   k := k + (b mod 10);
   b := b div 10;
 end;
a:=a-k;
i:=i+1;
end;
write (i);
end.