sqlite3, 303 bytes

Result

AC

Duration

1042ms

Code [DL]

with x(i,j)as(select cast(substr(v,0,instr(v,'
'))as integer) as i,substr(v,instr(v,'
')+1)as j from i),c(k)as(values(1)union all select k+1 from c limit (select i from x))
select case when(k=1 or k=i)then replace(hex(zeroblob(j)),'00','*')else '*'||replace(hex(zeroblob(j-2)),'00',' ')||'*'end from x,c

stdin

28
23

stdout

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

stderr