非負 is read as ひふ (hifu) and means non-negative.
ひふ
hifu
ひふせいすう
non-negative integer
ひじょう
emergency
ひこう
delinquency
ひなん
criticism
ひじょうしき
lack of common sense
ひじょうぐち
emergency exit
ひこうしき
informal
ひこうかい
private
ひごうほう
illegal
ひれい
impoliteness
ひじょうに
very
ひ
fault