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