Pisces

题意翻译

给定一棵 $n$ 个节点的无根树，每条边带边权（单位公里）。有若干条无法区分的鱼，在第 $1$ 天，它们可以在任意的节点上。每一天它们都可以走一公里或待在原地不动，鱼的数量守恒，每个节点都能容纳任意数量的鱼。 有 $k$ 个条件，第 $j$ 个条件表示在第 $d_j$ 天有至少 $f_j$ 条鱼在节点 $p_j$ 里，求出在满足所有条件的情况下最少的鱼的数量。

题目描述

A group of researchers are studying fish population in a natural system of lakes and rivers. The system contains $ n $ lakes connected by $ n - 1 $ rivers. Each river has integer length (in kilometers) and can be traversed in both directions. It is possible to travel between any pair of lakes by traversing the rivers (that is, the network of lakes and rivers form a tree). There is an unknown number of indistinguishable fish living in the lakes. On day $ 1 $ , fish can be at arbitrary lakes. Fish can travel between lakes by swimming the rivers. Each fish can swim a river $ l $ kilometers long in any direction in $ l $ days. Further, each fish can stay any number of days in any particular lake it visits. No fish ever appear or disappear from the lake system. Each lake can accomodate any number of fish at any time. The researchers made several observations. The $ j $ -th of these observations is "on day $ d_j $ there were at least $ f_j $ distinct fish in the lake $ p_j $ ". Help the researchers in determining the smallest possible total number of fish living in the lake system that doesn't contradict the observations.

输入输出格式

输入格式

The first line contains a single integer $ n $ ( $ 1 \leq n \leq 10^5 $ ) — the number of lakes in the system. The next $ n - 1 $ lines describe the rivers. The $ i $ -th of these lines contains three integers $ u_i $ , $ v_i $ , $ l_i $ ( $ 1 \leq u_i, v_i \leq n $ , $ u_i \neq v_i $ , $ 1 \leq l_i \leq 10^3 $ ) — $ 1 $ -based indices of lakes connected by the $ i $ -th river, and the length of this river. The next line contains a single integer $ k $ ( $ 1 \leq k \leq 10^5 $ ) — the number of observations. The next $ k $ lines describe the observations. The $ j $ -th of these lines contains three integers $ d_j $ , $ f_j $ , $ p_j $ ( $ 1 \leq d_j \leq 10^8 $ , $ 1 \leq f_j \leq 10^4 $ , $ 1 \leq p_j \leq n $ ) — the day, the number of fish, and the lake index of the $ j $ -th observation. No two observations happen on the same day at the same lake simultaneously.

输出格式

Print one integer — the smallest total number of fish not contradicting the observations.

输入输出样例

输入样例 #1

4
1 2 1
1 3 1
1 4 1
5
1 1 2
1 1 3
2 2 1
3 1 4
3 1 2

输出样例 #1

2

输入样例 #2

5
1 2 1
1 3 1
1 4 1
1 5 1
4
1 1 2
2 1 3
3 1 4
4 1 5

输出样例 #2

2

输入样例 #3

5
2 5 1
5 1 1
2 4 1
5 3 3
6
5 2 4
2 1 1
2 1 3
2 2 4
4 7 5
4 1 2

输出样例 #3

10

说明

In the first example, there could be one fish swimming through lakes $ 2 $ , $ 1 $ , and $ 4 $ , and the second fish swimming through lakes $ 3 $ , $ 1 $ , and $ 2 $ . In the second example a single fish can not possibly be part of all observations simultaneously, but two fish swimming $ 2 \to 1 \to 4 $ and $ 3 \to 1 \to 5 $ can. In the third example one fish can move from lake $ 1 $ to lake $ 5 $ , others staying in their lakes during all time: two fish in lake $ 4 $ , six fish in lake $ 5 $ , one fish in lake $ 3 $ . The system of lakes is shown on the picture. 

题意翻译

给定一棵 $n$ 个节点的无根树，每条边带边权（单位公里）。有若干条无法区分的鱼，在第 $1$ 天，它们可以在任意的节点上。每一天它们都可以走一公里或待在原地不动，鱼的数量守恒，每个节点都能容纳任意数量的鱼。 有 $k$ 个条件，第 $j$ 个条件表示在第 $d_j$ 天有至少 $f_j$ 条鱼在节点 $p_j$ 里，求出在满足所有条件的情况下最少的鱼的数量。