  func f(n) {
    return n+1;
  }
  $o1 = f(NR);
  $o2 = f(f(NR));
  $o3 = f(f(f(NR)));
  $o4 = f(f(f(f(NR))));
  $o5 = f(f(f(f(f(NR)))));
  $o6 = f(f(f(f(f(f(NR))))));

