Nirvana

Description:

Input:

The only input line contains the integer $$$n$$$ ($$$1 \le n \le 2\cdot10^9$$$).

Output:

Print the maximum product of digits among all integers from $$$1$$$ to $$$n$$$.

Sample Input:

390

Sample Output:

216

Sample Input:

7

Sample Output:

7

Sample Input:

1000000000

Sample Output:

387420489

Note:

In the first example the maximum product is achieved for $$$389$$$ (the product of digits is $$$3\cdot8\cdot9=216$$$).

In the second example the maximum product is achieved for $$$7$$$ (the product of digits is $$$7$$$).

In the third example the maximum product is achieved for $$$999999999$$$ (the product of digits is $$$9^9=387420489$$$).