CF 152 B. Chilly Willy

 

B. Chilly Willy
time limit per test
2 seconds
memory limit per test
256 megabytes
input
standard input
output
standard output

Chilly Willy loves playing with numbers. He only knows prime numbers that are digits yet. These numbers are 2, 3, 5 and 7. But Willy grew rather bored of such numbers, so he came up with a few games that were connected with them.

Chilly Willy wants to find the minimum number of length n, such that it is simultaneously divisible by all numbers Willy already knows (2, 3, 5 and 7). Help him with that.

A number's length is the number of digits in its decimal representation without leading zeros.

Input

A single input line contains a single integer n (1 ≤ n ≤ 105).

Output

Print a single integer — the answer to the problem without leading zeroes, or "-1" (without the quotes), if the number that meet the problem condition does not exist.

Sample test(s)
Input
1
Output
-1
Input
5
Output
10080




水题,找到它的周期就好了。
n==1||n==2输出-1,至少210.
n==3 210.


然后后面就是以六个数为一个周期。

posted on 2012-11-26 10:29  仁者无敌8勇者无惧  阅读(342)  评论(0编辑  收藏  举报

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