Find the Internet checksum of the four $16-$bit words: $(1111111111111111,1111111100000000,1111000011110000,1100000011000000).$ Note that the Internet checksum can detect a single error occurring in any of the $16-$bit words. Convince yourself that it cannot detect all double error patterns, i$.$e$.$ two errors in the same $16-$bit word or one error in one word and another in another word.