A company must meet the following demands for cash at the beginning of each of the next four months: month $1,220$; month $2,220$; month $3,210$; month $4,240.$ At the beginning of month $1$ the company has $471$ in cash and $285$ worth of bond $1,405$ worth of bond $2,$ and $270$ worth of bond $3.$ The company have to sell some bonds to meet demands, but the penalty will be charged for any bonds sold before the end of month $4.$ The penalties for selling $1$ worth of each bond are as shown in the table below. The penalties have to be paid in cash. the penalty for selling bonds $1,2,3$ in month one is $0\mathrm{.}95,0\mathrm{.}6,0\mathrm{.}55$ respectively in pounds. the penalty for selling bonds $1,2,3$ in month two is $0\mathrm{.}7,0\mathrm{.}7,0\mathrm{.}75$ respectively in pounds. the penalty for selling bonds $1,2,3$ in month three is $0\mathrm{.}55,0\mathrm{.}0,0\mathrm{.}85$ respectively in pounds. the penalty for selling bonds $1,2,3$ in month four is $0\mathrm{.}7,0\mathrm{.}0,0\mathrm{.}0$ respectively in pounds. What is the minimal cost $($i$.$e$.$ the sum of all penalties paid$)$ of meeting cash demands for the next four months? $($Fractions of bonds can be sold.$)$