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

