#include <bits/stdc++.h>                                                                          
                                                                                                  
using namespace std;                                                                              
                                                                                                  
#define all(x) x.begin(), x.end()                                                                 
#define rep(i, n) for (int i = 0; i < n; ++i)                                                     
#define reps(i, m, n) for (int i = m; i <= n; ++i)                                                
                                                                                                  
using i64 = long long;                                                                            
using pii = pair<i64, i64>;                                                                       
                                                                                                  
template<class A, class B>inline bool chmax(A &a, const B &b){return b > a ? a = b,1 : 0;}        
template<class A, class B>inline bool chmin(A &a, const B &b){return b < a ? a = b,1 : 0;}        
                                                                                                  
constexpr int INF = 0x3f3f3f3f;                                                                   
constexpr i64 LINF = 0x3f3f3f3f3f3f3f3fLL;                                                        
constexpr int MOD = int(1e9) + 7;                                                                 
                                                                                                  
signed main()                                                                                     
{                                                                                                 
  ios::sync_with_stdio(false);                                                                    
  cin.tie(nullptr);                                                                               
                                                                                                  
  int h, w;                                                                                       
  cin >> h >> w;                                                                                  
                                                                                                  
  char c[128][128];                                                                               
  reps(i, 1, h) {                                                                                 
    reps(j, 1, w) {                                                                               
      cin >> c[i][j];                                                                             
    }                                                                                             
  }                                                                                               
                                                                                                  
  reps(i, 0, h+1) {                                                                               
    reps(j, 0, w+1) {                                                                             
      if (i == 0 || j == 0 || i == h+1 || j == w+1) cout << '#';                                  
      else cout << c[i][j];                                                                       
    }                                                                                             
    cout << "\n";                                                                                 
  }                                                                                               
                                                                                                  
  return 0;                                                                                       
}                                                                                                 

Measured memory_bytes: 256