static int indexOfElementThatContains(L<S> l, S s) {
  for i over l:
    if (contains(l.get(i), s))
      ret i;
  ret -1;
}

static int indexOfElementThatContains(L<S> l, int i, S s) {
  for (; i < l(l); i++)
    if (contains(l.get(i), s))
      ret i;
  ret -1;
}