rust, 201 bytes

Result

AC

Duration

1247ms

Code [DL]

use std::io::*;fn main(){let mut b=[0;9];let(_,h,w)=(stdin().read(&mut b),(b[0]-48)*10+b[1]-48,(b[3]-48)*10+b[4]-50);for y in 0..h{println!("*{}*",(if y==0||y==h-1{"*"}else{" "}).repeat(w as usize));}}

stdin

29
31

stdout

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

stderr