crystal, 76 bytes

Result

WA

Duration

1937ms

Code [DL]

s=gets
if s
h=s.to_i-2
w=s.to_i-1
a="*"*w+"**
"
puts a+"*#{" "*w}*
"*h+a
end

stdin

10
82

stdout

***********
*         *
*         *
*         *
*         *
*         *
*         *
*         *
*         *
***********

stderr