20
18
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000011111111111000
000111111111111100
001111111111111110
011111100000111110
011110000000011111
111110000000001100
111100000000000000
111100000000000000
111100000000000000
111100000000000000
111100000000000000
111100000000001100
111110000000011111
011110000000011111
011111100001111110
001111111111111110
000111111111111100
000011111111111000
000000111111100000
