Ali is Hamed's little brother and tomorrow is his birthday. Hamed wants his brother to earn his gift so he gave him a hard programming problem and told him if he can successfully solve it, he'll get him a brand new laptop. Ali is not yet a very talented programmer like Hamed and although he usually doesn't cheat but this time is an exception. It's about a brand new laptop. So he decided to secretly seek help from you. Please solve this problem for Ali. An n -vertex weighted rooted tree is given. Vertex number 1 is a root of the tree. We define d(u, v) as the sum of edges weights on the shortest path between vertices u and v . Specifically we define d(u, u) = 0. Also let's define S(v) for each vertex v as a set containing all vertices u such that d(1, u) = d(1, v) + d(v, u). Function f(u, v) is then defined using the following formula: The goal is to calculate f(u, v) for each of the q given pair of vertices. As the answer can be rather large it's enough to print it modulo 109 + 7.
输入描述:
In the first line of input an integer n (1 ≤ n ≤ 105), number of vertices of the tree is given.In each of the next n - 1 lines three space-separated integers ai, bi, ci (1 ≤ ai, bi ≤ n, 1 ≤ ci ≤ 109) are given indicating an edge between ai and bi with weight equal to ci.In the next line an integer q (1 ≤ q ≤ 105), number of vertex pairs, is given.In each of the next q lines two space-separated integers ui, vi (1 ≤ ui, vi ≤ n) are given meaning that you must calculate f(ui, vi).It is guaranteed that the given edges form a tree.


输出描述:
Output q lines. In the i-th line print the value of f(ui, vi) modulo 109 + 7.
示例1

输入

5<br />1 2 1<br />4 3 1<br />3 5 1<br />1 3 1<br />5<br />1 1<br />1 5<br />2 4<br />2 1<br />3 5<br />8<br />1 2 100<br />1 3 20<br />2 4 2<br />2 5 1<br />3 6 1<br />3 7 2<br />6 8 5<br />6<br />1 8<br />2 3<br />5 8<br />2 6<br />4 7<br />6 1<br />

输出

10<br />1000000005<br />1000000002<br />23<br />1000000002<br />999968753<br />49796<br />999961271<br />999991235<br />999958569<br />45130<br />
加载中...