Q1:B.i=f(A.s) // B is taking value from A, So, B is taking value from it's left side. It is L attributed.
L2:S.s=f(B.s) // S is taking value from B.// it is S attributed. If attribute is S attributed, then it is obviously L attributed.
Q2:R.i=f(P.i) // R is taking value from it's parent . It is L attributed
Q.i=f(R.s) //Q taking value from it's right sibling. It is not L attributed