Priyanshu and Family tree

Priyanshu was drawing his family tree and came up with an interesting problem. Given a tree with $n$ nodes and $n-1$ edges always rooted at $1$ . Each node $i$ has a number $A_i$ associated with it. You are given $Q$ queries to solve where in each query you will be given two numbers $x$ and $k$. **You have to find the sum of values of all the kth children of node x** . **If kth children of node