求模逆元

def solve(____):
    def extended_gcd(____):
        if a == ____:
            return b, ____, ____
        gcd, x1, y1 = extended_gcd(____)
        return gcd, y1 - (____) * x1, x1
    gcd, x, _ = extended_gcd(____)
    if gcd != ____:
        print(____)
    else:
        print((____) % n)