Input (grade 13): The six editions of his An Essay on the Principle of Population, published from 1798 to 1826, observed that sooner or later population gets checked by famine and disease.
Output (grade 8): There were six editions of his An Essay on the Principle of Population, published from 1798 to 1826. He said that sooner or later population gets checked, by famine, disease, and widespread mortality.