Extract smallest amount from 2 rows and it should continue the whole sheet

need to extract smaller amount from two rows for example
51000
5000
smaller amount should cut and paste to next line.
it should continue the whole sheet.. the common line is 0 after each two amounts and it should skip if there is only one number in the row.
51000
5000
0
10000
1000
0
250
0
3000
0
8100
810