Programming in C: Find the Output of function call A(6). Please explain the approach for such questions closed

Question

A(n)

{if(n<1) return (1);

else return A(n-2)+B(n-1);}

B(n)

{if(n<=1)   return 1;

else  return B(n-1)+A(n-2);}

Comments

It can be solved by drawing recursive tree.