The objective function is to raise funds initially, with the least requirements.
There are several limiting factors. One is that the money in each time node must be enough to pay. Note that the money at each node includes bonds and bank interest income, and bonds that have not expired will be deducted.
The other is that the purchase restriction itself is a constraint.
Furthermore, xyz is greater than or equal to 0.
These functions are slowly pushed back from the first year, as long as they meet the conditions.