docs: private int modInverse(int x) {
  		// Cube gives inverse mod 2^4, as x^4 == 1 (mod 2^4) for all odd x.
  		int inverse = x * x * x;
  		// Newton iteration doubles correct bits at each step.
  		inverse *= 2 - x * inverse;
  		inverse *= 2 - x * inverse;
  		inverse *= 2 - x * inverse;
  		return inverse;
  	}