You are given a tree consisting of $$n$$ nodes.
You can select any number of nodes from the tree that you want to save. The remaining nodes will be destroyed but the saved nodes again form a tree.
Find the total number of such ways to form the tree.
Note: You may not select any node or you may save all nodes.
Input format
Output format
Print the required number of ways modulo $$10^9 + 7$$.
You has these options {},{0},{1},{2},{0,1},{1,2},{0,2}, {0,1,2}. Out of these, only 7 are valid trees as {0,2} does not form a single tree.