the codes seems doesn't work for 3grams and 4grams

[shichenjingya]

HI! Thank you so much for providing the codes for downloading and filtering google ngrams! But it seems that the codes do not work when I set the ngram parameter as 3 or 4, and the message says "wc: 3gram-raw/eng/googlebooks-eng-all-3gram-20120701-: open: No such file or directory
cat: 3gram-filtered/eng/googlebooks-eng-all-3gram-20120701-.filtered: No such file or directory". I am a newcomer to coding, and much appreciate it if you could give me a hand!