Problem7919--USACO 2017 January Contest, Silver —— Problem 3. Secret Cow Code

7919: USACO 2017 January Contest, Silver —— Problem 3. Secret Cow Code

[Creator : ]
Time Limit : 1.000 sec  Memory Limit : 256 MiB

Description

The cows are experimenting with secret codes, and have devised a method for creating an infinite-length string to be used as part of one of their codes. 
Given a string $s$, let $F(s)$ be s followed by s "rotated" one character to the right (in a right rotation, the last character of s rotates around and becomes the new first character). 
Given an initial string $s$, the cows build their infinite-length code string by repeatedly applying $F$; each step therefore doubles the length of the current string.
Given the initial string and an index $N$, please help the cows compute the character at the $N$-th position within the infinite code string.

Input

The input consists of a single line containing a string followed by $N$. The string consists of at most $30$ uppercase characters, and $N≤10^{18}$. Note that $N$ may be too large to fit into a standard 32-bit integer, so you may want to use a 64-bit integer type (e.g., a "long long" in C/C++).

Output

Please output the $N$-th character of the infinite code built from the initial string. The first character is $N=1$.

Sample 1 Input

COW 8

Sample 1 Output

C
In this example, the initial string COW expands as follows:


COW -> COWWCO -> COWWCOOCOWWC
                 12345678


HINT

相同题目:USACO Silver

Source/Category