Vernon purchases a $19-$year, zero$-$coupon bond that matures for $1650.$ The bond is priced to yield $5\%$ annual effective. Vernon sells the bond to Wendy N years after she purchased it$.$ The price paid by Wendy results in an annual effective yield of $5\mathrm{.}8\%$ for Vernon and an annual effective yield of $4\mathrm{.}2\%$ for Wendy. Find N$.$