Score : $100$ points
Find the $X$-th character from the beginning of the string that is obtained by concatenating these characters: $N$ copies of A's, $N$ copies of B's, …, and $N$ copies of Z's, in this order.
Input is given from Standard Input in the following format:
$N$ $X$
Print the answer.
1 3
C
We obtain the string ABCDEFGHIJKLMNOPQRSTUVWXYZ, whose $3$-rd character from the beginning is C.
2 12
F
We obtain the string AABBCCDDEEFFGGHHIIJJKKLLMMNNOOPPQQRRSSTTUUVVWWXXYYZZ, whose $12$-th character from the beginning is F.