const int MAXN=1e3+10;
int n,m;
char a[MAXN][MAXN];
inline void solve(){
	scanf("%d%d",&n,&m);
	for(int i=0;i<=n+1;i++)
	{
		for(int j=0;j<=m+1;j++)
		{
			a[i][j]='#';
		}
	}
	a[n+1][m+1]='.';
	for(int i=0;i<=n+1;i++)
	{
		for(int j=0;j<=m+1;j++)
		{
			putchar(a[i][j]);
		}
		putchar('\n');
	}
}

warning: writing 1 byte into a region of size 0 [-Wstringop-overflow=]
      |         a[n+1][m+1]='.';
      |         ~~~~~~~~~~~^~~~
note: destination object 'a' of size [1020100, 0]
      | char a[MAXN][MAXN];