If the letters of the word are arranged as in dictionary. m and n are the rank of the words
BULBUL and NANNU respectively, then the value of m-4n is _____

$$\begin{gathered} \text{ For BULBUL, the letters in alphabetical order are BBLLUU } \\ \begin{array}{r}BB\to \frac{4!}{2!2!}=6\\ BL\to \frac{4!}{2!}=12\\ BUB\to \frac{3!}{2!}=3\\ \mathrm{BULBLU}\to 1\\ \mathrm{BULBUL}\to 1\\ \therefore m=6+12+3+1+1=23\\ \text{ The letters in alphabetical order are ANNNU }\\ \begin{array}{r}A\to \frac{4!}{3!}=4\\ \mathrm{NANNU}\to 1\\ \therefore n=4+1=5\\ \text{ hence, }m-4n=23-20=3\end{array}\end{array} \end{gathered}$$