static S nth(int i) {
  S s = "th";
  int tens = (i % 100)/10;
  if (tens != 1) {
    if ((i % 10) == 1) s = "st";
    if ((i % 10) == 2) s = "nd";
  }
  if ((i % 10) == 3) s = "rd";
  ret i + s;
}