当前没有测试数据。

Description

Your task is to calculate the number of bit strings of length n.

For example, if n=3, the correct answer is 8, because the possible bit strings are 000, 001, 010, 011, 100, 101, 110, and 111.

Input Format

The only input line has an integer n.

Output Format

Print the result modulo 10⁹+7.

3

8

Hint

1≤n≤10⁶

Source

CSES