def isPrimeA(N):
    if N < 2:
        return False
    for i in range(2,N):
        if N % i == 0:
            return False
    return True

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