const r:array[0..19] of byte=(
  0,1,5,2,8,3,9,2,8,7,7,8,4,7,3,8,4,1,5,4
);
var s:string;
    nr,err:byte;
begin
  assign(input,'cifra.in'); reset(input);
  assign(output,'cifra.out'); rewrite(output);
  readln(s);
  if length(s)>2 then delete(s,1,length(s)-2);
  val(s,nr,err);
  write((4*(nr div 20)+r[nr mod 20])mod 10);
  close(input); close(output);
end.