#D3803. Infinite Sequence
Infinite Sequence
Infinite Sequence
How many infinite sequences a_1, a_2, ... consisting of {{1, ... ,n}} satisfy the following conditions?
- The n-th and subsequent elements are all equal. That is, if n \leq i,j, a_i = a_j.
- For every integer i, the a_i elements immediately following the i-th element are all equal. That is, if i < j < k\leq i+a_i, a_j = a_k.
Find the count modulo 10^9+7.
Constraints
- 1 \leq n \leq 10^6
Input
Input is given from Standard Input in the following format:
n
Output
Print how many sequences satisfy the conditions, modulo 10^9+7.
Examples
Input
2
Output
4
Input
654321
Output
968545283
inputFormat
Input
Input is given from Standard Input in the following format:
n
outputFormat
Output
Print how many sequences satisfy the conditions, modulo 10^9+7.
Examples
Input
2
Output
4
Input
654321
Output
968545283
样例
654321
968545283