Consider a retirement savings account where the monthly contribution is$$$$115$for the first$25$years$,$ is increased to$$$$215$for the next$15$years$,$ and then is increased once again to$$$$425$for the last$5$years$.$ The APR is always$6\mathrm{.}4\%$compounded monthly. What is the value of the account at the end of$45$years$?$The value of the account at the end of$45$years is $\_\_\_\_?$