csharp, 176 bytes

Result

AC

Duration

1185ms

Code [DL]

using static System.Console;class A{static int r()=>int.Parse(ReadLine());static void Main(){for(int h=r(),w=r(),i=++w*h;i-->0;)Write(-~i%w>2&i>w&i<w*h-w?" ":i%w>0?"*":"\n");}}

stdin

24
81

stdout

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

stderr