L={$\epsilon$,a,b,ab,ba,aa,bb,..}
Trying to generate every string by using the condition
For example assume string aa X=$\epsilon$ and Y=aa===> na(X)=0 and nb(y)=0 which is equal so it can be in the language. Similarly we can do this for any string. so L=$(a+b)^*$ which is regular.
Correct me if I'm wrong