Evaluate (−1p)\left( \frac{-1}{p} \right)(p−1) for an odd prime ppp.
111 if p≡1(mod4)p \equiv 1 \pmod 4p≡1(mod4), and −1-1−1 if p≡3(mod4)p \equiv 3 \pmod 4p≡3(mod4)
111 if p≡3(mod4)p \equiv 3 \pmod 4p≡3(mod4)
111 always
−1-1−1 always