How to lower the cost $($to $9,055,000$ or lower$)$ of this with these parameters:

Maximum regular hours per worker per quarter: $450$

Maximum overtime hours per worker per quarter: $100$

Maximum number of workers: $85$

Starting workforce: $55$

Hiring cost per worker: $2000$

Firing cost per worker: $1400$

Regular time wage: $30$

Overtime wage: $45$

Subcontract Cost: $125$

Back order cost: $100$

Holding cost per pair of shoes per quarter: $1$

Ending Inventory Period $0$: $3000$

Current total Total Cost $$9,333,083\mathrm{.}00$

target: $9,055,000$

Quarter $12345678$

Aggregate demand in order of quarters: $2624527110295103749049030518154080536845$

Current Excel Spread:

Period $12345678$

Forecast $2624527110295103749049030518154080536845$

Production

Regular Time $(30)3735837357382503825038250382503825038250$

Overtime $(45)$

Subcontract $(125)$

Total Production $3735737357382503825038250382503825038250$

Number of Workers Start $(55)8383858585858585$

Inventory

Beginning $3000141122435933099338592307995146959$

Ending $(3000)1411224359330993385923079951469598364$

Average $855619235\mathrm{.}528729334792846916296\mathrm{.}58236\mathrm{.}57661\mathrm{.}5$

Backlog

Labor Costs

Regular $(30)11207101120710114750011475001147500114750011475001147500$

Overtime $(45)00000000$

Subcontract $(125)00000000$

Hire $(2000)560000400000000$

Fire $(1400)00000000$

Total Labor Cost $11767101120710115150011475001147500114750011475001147500$

Inventory Costs

Holding Cost $(1)855619235\mathrm{.}528729334792846916296\mathrm{.}58236\mathrm{.}57661\mathrm{.}5$

Back Order $(100)00000000$

Total Production Cost $11852661139945\mathrm{.}51180229118097911759691163796\mathrm{.}51155736\mathrm{.}51155161\mathrm{.}5$

these parameters cannot be changed, we need exact numbers to change do not use slack variables