I can not solve this exercise:
"Find the language generated by the regular grammar $G = (\{S, A, B\},\{a, b\}, P, S)$, with P given by $S\to\lambda/aB/bA,\; A\to bB,\; B\to bS$. Express it by a regular expression."
It is clear that it will generate an infinite language, but by making the derivation tree, with these productions, I find it hard to see the generated language. Some help?
Thanks!