题目描述
We have a tree G with N vertices numbered 1 to N. The i-th edge of G connects Vertex a_i and Vertex b_i.
Consider adding zero or more edges in G, and let H be the graph resulted.
Find the number of graphs H that satisfy the following conditions, modulo 998244353.
- H does not contain self-loops or multiple edges.
- The diameters of G and H are equal.
- For every pair of vertices in H that is not directly connected by an edge, the addition of an edge directly connecting them would reduce the diameter of the graph.
Constraints
- $3 \le N \le 2 \times 10^5$
- $1 \le a_i, b_i \le N$
- The given graph is a tree.
Input
Input is given from Standard Input in the following format:
N
a_1 b_1
$\vdots$
a_{N-1} b_{N-1}
Output
Print the answer.
Examples
Input
6
1 6
2 1
5 2
3 4
2 3
Output
3
Input
3
1 2
2 3
Output
1
Input
9
1 2
2 3
4 2
1 7
6 1
2 5
5 9
6 8
Output
27
Input
19
2 4
15 8
1 16
1 3
12 19
1 18
7 11
11 15
12 9
1 6
7 14
18 2
13 12
13 5
16 13
7 1
11 10
7 17
Output
78732
输入格式
见题面
输出格式
见题面
样例输入
9
1 2
2 3
4 2
1 7
6 1
2 5
5 9
6 8
样例输出
27