Compute the frequency of high frequency external signal using frequency measurement method $1$ in STM$32.[4]$

Consider the followings for the calculation:

i$)$ Timer $1($TIMI$)$ is running on external signal and timer $2($TIM$2)$ is running on internal signal of CK$\_$PSC$2=8$ MHz$.$

ii$)$ The ARR and PSC settings of timer $2$ are as follows ARR$279$ and PSC$2-15.$ The ARR and PSC values of timer I are ARR$1=1999$ and PSC$1=0.$

iii$)$ Timer $1$ starts running at first update event interrupt generated by timer $2$ and stops at

second update event interrupt generated by timer $2.$ iv$)$ Between the first and second update event interrupt generated by timer $2,$ the timer $1$ rolls

back $4$ times and CNTI value was $800$ when timer $1$ stops.

v$)$ All the mentioned numbers are in decimal number system.