6174

uses crt;
var
  st:string;
  n:longint;

function num(x:char):longint;
begin
  num:=ord(x)-48;
end;

procedure swap(var x,y:char);
var tmp:char;
begin
  tmp:=x; x:=y; y:=tmp;
end;

function sort(st:string;bool:boolean):longint;
var i,j:longint;
begin
  for i:=1 to n do
    for j:=i+1 to n do
      if (num(st[i]) > num(st[j]) = bool) then
        swap(st[i],st[j]);
  val(st,sort);
end;

procedure solve();
var sub,c:longint;
begin
  c:=0;
  readln(st);
  n:=length(st);
  repeat
    begin
      sub:=sort(st,false)-sort(st,true);
      str(sub,st);
      inc(c);
    end;
  until (sub=6174);
  writeln(c);
end;

begin
  clrscr();
  solve();
  readln();
end.