Nirvana

题意翻译

给出n，求1到n每个数字的每一位乘积的最大值

题目描述

Kurt reaches nirvana when he finds the product of all the digits of some positive integer. Greater value of the product makes the nirvana deeper. Help Kurt find the maximum possible product of digits among all integers from $ 1 $ to $ n $ .

输入输出格式

输入格式

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

输出格式

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

输入输出样例

输入样例 #1

390

输出样例 #1

216

输入样例 #2

7

输出样例 #2

7

输入样例 #3

1000000000

输出样例 #3

387420489

说明

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 $ ).