flow.size: 8
row.1: 0,0,0,0,0,7,0,0
row.2: 0,4,0,0,0,0,1,7
row.3: 0,2,9,0,0,0,6,0
row.4: 0,0,0,4,3,0,8,0
row.5: 3,0,0,5,0,0,0,0
row.6: 1,2,0,9,0,0,0,0
row.7: 0,5,0,0,0,0,8,0
row.8: 0,0,0,0,0,0,6,0








