text: #include <bits/stdc++.h>
  using namespace std;
  
  typedef long long int llint;
  typedef unsigned long long int ullint;
  typedef short int sint;
  #define endn "\n"
  #define umap unordered_map
  #define uset unordered_set
  
  int main(void) {
      ios_base::sync_with_stdio(false);
      cin.tie(NULL); cout.tie(NULL);
  
      int n, m;
      cin >> n >> m;
  
      string hash_str, dot_str;
      for (int i = 1; i < m; i++) {
          hash_str += '#';
          dot_str += '.';
      }
      hash_str += '#';
  
      bool flag = true;
      for (int i = 1; i <= n; i++) {
          if (i % 2 == 0) {
              if (flag) {
                  cout << dot_str << '#' << endn;
                  flag = false;
              }
              else {
                  cout << '#' << dot_str << endn;
                  flag = true;
              }
          }
          else {
              cout << hash_str << endn;
          }
      }
      
  }
  // Solved By: shihab4t
  // Wednesday, July 14, 2021 | 08:43:19 PM (+06)
  