#include <bits/stdc++.h>
using namespace std;
int main() {
  for (int W = 0;; W++) {
    int A, B;
    cin >> A >> B;
    for (int X = 0; X < A; X++) {
      if (X % 2 == 0) {
        for (int Y1 = 0; Y1 < B; Y1++) {
          if (Y1 % 2 == 0) {
            cout << "#";
          } else
            cout << ".";
        }
        cout << endl;
      } else
        for (int Y2 = 0; Y2 < B; Y2++) {
          if (Y2 % 2 == 0) {
            cout << ".";
          } else
            cout << "#";
        }
      cout << endl;
      cout << endl;
    }
  }
}
