The tree with $n$ vertices is given. The edges of the tree have weights of only $0$ or $1$. Let’s find the \textbf{XOR} sum between all pairs of vertices. Compute the sum of all \textbf{XOR} sums. \InputFile The first line contains the number of vertices $n~(2 \le n \le 10^5)$ in the graph. The next $n - 1$ lines describe the edges. Each line contains three integers: the numbers of the vertices connected by the edge (vertices are numbered from $1$ to $n$) and the weight of the edge ($0$ or $1$). \OutputFile Print the sum of \textbf{XOR} sums between all pairs of vertices. \includegraphics{https://static.e-olymp.com/content/9a/9a213047daca2e90c73ce7c67169f126ad1eea6f.gif}