Shohag has a tree with $n$ nodes.
Pebae has an integer $m$. She wants to assign each node a value — an integer from $1$ to $m$. So she asks Shohag to count the number, modulo $998\,244\,353$, of assignments such that following conditions are satisfied:
- For each pair
$1 \le u \lt v \le n$, the least common multiple (LCM) of the values of the nodes in the unique simple path from$u$to$v$is not divisible by the number of nodes in the path. - The greatest common divisor (GCD) of the values of all nodes from
$1$to$n$is$1$.
But this problem is too hard for Shohag to solve. As Shohag loves Pebae, he has to solve the problem. Please save Shohag!
Input
The first line contains two space-separated integers $n$ and $m$ ($2 \le n \le 10^6$, $1 \le m \le 10^{9}$).
Each of the next $n - 1$ lines contains two integers $u$ and $v$ ($1 \le u, v \le n$) indicating there is an edge between vertices $u$ and $v$. It is guaranteed that the given edges form a tree.
Output
Print a single integer — the number of valid ways to assign each vertex a value, modulo $998\,244\,353$.
Note
In the first test case, the valid assignments are $[1, 1, 1, 1, 1, 1]$ and $[1, 1, 1, 1, 1, 5]$.
In the second test case, the valid assignments are $[1, 1]$, $[1, 3]$, $[1, 5]$, $[3, 1]$, $[3, 5]$, $[5, 1]$ and $[5, 3]$.
样例
6 6
1 2
2 3
3 4
4 5
3 6
2
2 5
1 2
7
12 69
3 5
1 4
2 3
4 5
5 6
8 9
7 3
4 8
9 10
1 11
12 1
444144548
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