P25783 [AtCoder] GCD cost on the tree
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题目描述

Problem Statement

You are given an undirected tree with N vertices.
Let us call the vertices Vertex $1, Vertex 2, \ldots, Vertex N$. For each $1\leq i\leq N-1$, the i-th edge connects Vertex U_i and Vertex V_i.
Additionally, each vertex is assigned a positive integer: Vertex i is assigned A_i.
The cost between two distinct vertices s and t, C(s,t), is defined as follows.

Let $p_1(=s), p_2, \ldots, p_k(=t)$ be the vertices of the simple path connecting Vertex s and Vertex t, where k is the number of vertices in the path (including the endpoints).
Then, let $C(s,t)=k\times \gcd (A_{p_1},A_{p_2},\ldots,A_{p_k})$,
where $\gcd (X_1,X_2,\ldots, X_k)$ denotes the greatest common divisor of $X_1,X_2,\ldots, X_k$.

Find $\displaystyle\sum_{i=1}^{N-1}\sum_{j=i+1}^N C(i,j), modulo 998244353$.

Input

Input is given from Standard Input in the following format:
N
$A_1 A_2 \cdots A_N$
U_1 V_1
U_2 V_2
$\vdots$
U_{N-1} V_{N-1}

Output

Print $\displaystyle\sum_{i=1}^{N-1}\sum_{j=i+1}^N C(i,j), modulo 998244353$.

Constraints

  • $2 \leq N \leq 10^5$
  • $1 \leq A_i\leq 10^5$
  • $1\leq U_i<V_i\leq N$
  • All values in input are integers.
  • The given graph is a tree.

Sample Input 1

4
24 30 28 7
1 2
1 3
3 4

Sample Output 1

47

There are edges directly connecting Vertex 1 and 2, Vertex 1 and 3, and Vertex 3 and 4.
Thus, the costs are computed as follows.

  • $C(1,2)=2\times \gcd(24,30)=12$
  • $C(1,3)=2\times \gcd(24,28)=8$
  • $C(1,4)=3\times \gcd(24,28,7)=3$
  • $C(2,3)=3\times \gcd(30,24,28)=6$
  • $C(2,4)=4\times \gcd(30,24,28,7)=4$
  • $C(3,4)=2\times \gcd(28,7)=14$

Thus, the sought value is $\displaystyle\sum_{i=1}^{3}\sum_{j=i+1}^4 C(i,j)=(12+8+3)+(6+4)+14=47 modulo 998244353,$ which is 47.

Sample Input 2

10
180 168 120 144 192 200 198 160 156 150
1 2
2 3
2 4
2 5
5 6
4 7
7 8
7 9
9 10

Sample Output 2

1184

输入格式

见题面 Input 部分

输出格式

见题面 Output 部分

样例输入
4 24 30 28 7 1 2 1 3 3 4
样例输出
47