19
16
1111000000011111
1111000000111110
1111000001111100
1111000011111000
1111000111110000
1111001111100000
1111011111000000
1111111110000000
1111111111000000
1111111111100000
1111111111100000
1111110111110000
1111100011110000
1111000001111000
1111000001111100
1111000000111100
1111000000111110
1111000000011111
1111000000001111
