A-Number and B-Number

Time Limit: 1000 ms Memory Limit: 65536 KiB

Problem Description

    Tom is very interested in number problem. Nowadays he is thinking of a problem about A-number and B-number.
    A-number is a positive integer whose decimal form contains 7 or it can be divided by 7. We can write down the first 10 A-number ( a[i] is the ith A-number) 
         {a[1]=7,a[2]=14,a[3]=17,a[4]=21,a[5]=27,a[6]=28,a[7]=35,a[8]=37,a[9]=42,a[10]=47};
    B-number is Sub-sequence of A-number which contains all A-number but a[k] ( that k is a  A-number.)  Like 35, is the 7th A-number and 7 is also an A-number so the 35 ( a[7] ) is not a B-number. We also can write down the first 10 B-number.

         {b[1]=7,b[2]=14,b[3]=17,b[4]=21,b[5]=27,b[6]=28,b[7]=37,b[8]=42,b[9]=47,b[10]=49};
    Now Given an integer N, please output the Nth B-number

Input

The input consists of multiple test cases.

For each test case, there will be a positive integer N as the description.

Output

For each test case, output an integer indicating the Nth B-number.

You can assume the result will be no more then 2^63-1.

Sample Input

1
7
100

Sample Output

7
37
470

Hint

 

Source

2013年山东省第四届ACM大学生程序设计竞赛