September 10th is forester day. On this occasion Magic forest dwellers decided to make a party. Kuzma beaver is assigned to take care about intellectual games. Kuzma has invented at his opinion quite interesting game.</p>

Rules of the game are simple. Master announces positive integer N. Player needs to calculate product of digits for each positive integer up to N and report the greatest product.

All answers should be known beforehand to allow interactive communication during a game. This causes problems since N could be relatively big (1 ≤ N ≤ 2000000000). Kuzma is not good using computers; he asks you to write a program which having positive integer N will find correct answer.

입력 형식

Each line at input contains integer N.

출력 형식

Corresponding line at output should contain greatest product for this N.

예제 입력 1

1

예제 출력 1

1

예제 입력 2

101090000

예제 출력 2

43046721

예제 입력 3

28994

예제 출력 3

10368

예제 입력 4

4876

예제 출력 4

2268

예제 입력 5

2789

예제 출력 5

1008