P9298 [AtCoder] AtCoder Beginner Contest 172 - NEQ
提高-
题目描述

Count the pairs of length-N sequences consisting of integers between 1 and $M (inclusive), A_1, A_2, \cdots, A_{N}$ and $B_1, B_2, \cdots, B_{N}$, that satisfy all of the following conditions:

  • $A_i \neq B_i$, for every i such that $1\leq i\leq N$.
  • $A_i \neq A_j$ and $B_i \neq B_j$, for every (i, j) such that $1\leq i < j\leq N$.

Since the count can be enormous, print it modulo (10^9+7).

Constraints

  • $1\leq N \leq M \leq 5\times10^5$
  • All values in input are integers.

Input

Input is given from Standard Input in the following format:

N M

Output

Print the count modulo (10^9+7).

Examples

Input

2 2

Output

2

Input

2 3

Output

18

Input

141421 356237

Output

881613484

输入格式

见题面

输出格式

见题面

样例输入
141421 356237
样例输出
881613484