No of Words with length n

Q:There is a language with only two elements ie 'a' and 'bc'. How many words can be
made out of it if whose Length is n.

ex: if n=1, words are 'a' ans:1

if n=2, words are 'aa' 'bc' ans :2

Let N(k) be the number of strings of length k. Since you can
make a string of length k by appending 'a' onto a string of length k-1
or by appending 'bc' onto a string of length k-2, it follows that

N(k) = N(k-1) + N(k-2)

Furthermore, there are no strings of length -1 and only one string of
length 0.

code :

int getNoOfWords(int n){
if(n==1)
return 1;
else if(n = = 0 || n = = -1)
return 0;
else
return getNoOfWords(n-1)+getNoOfWords(n-2);
}