1
18 6
RQPONMLKJIHGFEDCBABCDEFGHIJKLMNOPQR
QPONMLKJIHGFEDCBABCDEFGHIJKLMNOPQ
PONMLKJIHGFEDCBABCDEFGHIJKLMNOP
ONMLKJIHGFEDCBABCDEFGHIJKLMNO
NMLKJIHGFEDCBABCDEFGHIJKLMN
MLKJIHGFEDCBABCDEFGHIJKLM
LKJIHG GHIJKL
KJIHGF FGHIJK
JIHGFE EFGHIJ
IHGFED DEFGHI
HGFEDC CDEFGH
GFEDCB BCDEFG
FEDCBABCDEF
EDCBABCDE
DCBABCD
CBABC
BAB
A