node, 153 bytes

Result

WA

Duration

1123ms

Code [DL]

a=[];p=process.stdin;p.on('data',s=>a.push(Number(s)));p.on('end',()=>{for(i=0;i<a[0];i++)console.log('*'+(i==0||i==a[0]-1?'*':' ').repeat(a[1]-2)+'*')})

stdin

11
48

stdout

stderr