Constant curve25519_dalek::constants::SQRT_MINUS_APLUS2

pub const SQRT_MINUS_APLUS2: FieldElement = FieldElement([-12222970, -8312128, -11511410, 9067497, -15300785, -241793,
              25456130, 14121551, -12187136, 3972024])

SQRT_MINUS_APLUS2 is sqrt(-486664)