U8_MAX = 0xFFFFFFFFFFFFFFFF
U16_MAX = U8_MAX << 64 | U8_MAX
U32_MAX = U16_MAX << 128 | U16_MAX

def dothex(num):
    strhex = hex(num)[2:]
    dothex = strhex[-16:]
    strhex = strhex[:-16]
    
    while len(strhex) > 0:
        dothex = strhex[-16:] + '.' + dothex
        strhex = strhex[:-16]

    return '0x' + dothex

print('mul16', dothex(U16_MAX * 2 % (U16_MAX + 1)))
print('mul32', dothex(U32_MAX * U16_MAX % (U32_MAX + 1)))