H-numbers

Problem Background

Special for beginners, ^_^

Problem Description

An H-number is a number whose prime factors contain only $2,3,5,7$, such as $630$ which is an H-number, while $22$ is not. Now output the $n$-th H-number. For convenience, define $H[1]=1$. It is known that $1\le n\le 10000$, and the final data is within the range of int64.

Input Format

One number $n$ (as described).

Output Format

The $n$-th H-number.

Sample Input 1

30

Sample Output 1

49

Sample Input 2

1

Sample Output 2

1

Hint

Brute force enumeration will overflow; use a generation method, preferably with optimization, otherwise the space complexity will be large.

Constraints

Time limit 1s, memory limit 1024KiB for each test case.