The hiragana syllable は (ha). Its equivalent in katakana is ハ (ha). It is the twenty-sixth syllable in the gojūon order; its position is は行あ段 (ha-gyō a-dan, “row ha, section a”).

難しい: difficult

imperfective and stem (or continuative) forms of なえる (naeru) [ichidan]

満点: perfect score / 満天: the whole sky