def isPrimeA(N):
if N < 2:return False
for i in range(2,N // 2 + 1):
if N % i == 0:return False
return True
def isPrimeB(N):
if N < 2:return False
for i in range(2, int(N ** 0.5) + 1):
if N % i == 0:return False
return True