20
18
111100000000001111
111110000000011111
011111000000111110
001111000000111100
001111100001111100
000111100001111000
000011110011110000
000011111111110000
000001111111100000
000000111111000000
000000111111000000
000000011110000000
000000011110000000
000000011110000000
000000011110000000
000000011110000000
000000011110000000
000000011110000000
000000011110000000
000000011110000000
