题解 | #判断两个IP是否属于同一子网#

while True:
    try:
        Mask = list(map(int, input().split('.')))
        Ip1 = list(map(int, input().split('.')))
        Ip2 = list(map(int, input().split('.')))

        Mask_str = ''

        note = 0
        counter = 0

        for i in range(4):
            if Mask[i] in range(0, 256) and Ip1[i] in range(0, 256) and Ip2[i] in range(0, 256):
                Mask_str += bin(Mask[i])[2:].zfill(8)
            else:
                note = 1
                break

        if Mask_str.rfind('1') + 1 != Mask_str.find('0') or note:
            print(1)
            continue
        
        for i in range(4):
            if (Ip1[i]) & (Mask[i]) == (Ip2[i]) & (Mask[i]):
                counter += 1
            else:
                break
        
        if counter == 4:
            print(0)
        else:
            print(2)

    except:
        break