A $$0.166$$ g sample of an organic compound was digested with conc. $$H_2SO_4$$ and then distilled with NaOH. The ammonia gas evolved was passed through $$50.0$$ mL of $$0.5$$ N $$H_2SO_4$$. The used acid required $$30.0$$ mL of $$0.25$$ N NaOH for complete neutralization. The mass percentage of nitrogen in the organic compound is ______