Input (grade 13): While the former is what the place name "Heligoland" normally is used to refer to, the latter is somewhat smaller, lower, surrounded by sand beaches and not permanently inhabited.
Output (grade 10): While the former is what the place name "Heligoland" normally is used to refer to, the latter is somewhat smaller (0.7 km ²), lower, surrounded by sand beaches and not permanently inhabited.