Assume that you arrange a mortgage of $$500,000$ at j$2=10\%($i$.$e$.10\%$ is a nominal annual rate; subscript $2$ refers to the compounding frequency, semi$-$annually$)$ amortized over $25$ years with monthly payments and a $5-$year term. You are permitted to prepay up to $10\%$ of the initial principal on the anniversary date $($namely$,$ at the end of $1$st yr$,2$nd yr$,...).$

If you only prepay $5\%$ of the initial principal at the end of the second year, what will be the OSB at the end of the term?