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

