Problem description
The use of letters can form some beautiful graphics , Here is an example ：
ABCDEFG
BABCDEF
CBABCDE
DCBABCD
EDCBABC
This is a 5 That's ok 7 The graph of the column , Please find out the law of this figure , And output a n That's ok m The graph of the column .
Input format
The input line , Contains two integers n and m, The number of columns representing the number of rows of the graph you want to output .
Output format
Output n That's ok , Every m Characters , For your graphics .
The sample input
5 7
Sample output
ABCDEFG
BABCDEF
CBABCDE
DCBABCD
EDCBABC
Data scale and agreement
1 <= n, m <= 26.
analysis ： Can be based on the first behavior
