#include <bits/stdc++.h>
using namespace std;
int main() {
  int H, W;
  cin >> H >> W;
  for (int s = 0; s < 10000; s++) {
    if (H % 2 == 0 && W % 2 == 0) {
      for (int i = 0; i < H / 2; i++) {
        for (int i1 = 0; i1 < W / 2; i1++) {
          cout << "#.";
        }
        cout << endl;
        for (int i2 = 0; i2 < W / 2; i2++) {
          cout << ".#";
        }
        cout << endl;
      }
    }
    if (H % 2 != 0 && W % 2 != 0) {
      for (int i = 0; i < H / 2; i++) {
        for (int i1 = 0; i1 < W / 2; i1++) {
          cout << "#.";
        }
        cout << "#";
        cout << endl;
        for (int i2 = 0; i2 < W / 2; i2++) {
          cout << ".#";
        }
        cout << "." << endl;
      }
      for (int i1 = 0; i1 < W / 2; i1++) {
        cout << "#.";
      }
      cout << endl;
    }
    if (H % 2 == 0 && W % 2 != 0) {
      for (int i = 0; i < H / 2; i++) {
        for (int i1 = 0; i1 < W / 2; i1++) {
          cout << "#.";
        }
        cout << "#";
        cout << endl;
        for (int i2 = 0; i2 < W / 2; i2++) {
          cout << ".#";
        }
        cout << "." << endl;
      }
      cout << endl;
    }
    if (H % 2 != 0 && W % 2 == 0) {
      for (int i = 0; i < H / 2; i++) {
        for (int i1 = 0; i1 < W / 2; i1++) {
          cout << "#.";
        }
        cout << endl;
        for (int i2 = 0; i2 < W / 2; i2++) {
          cout << ".#";
        }
        cout << endl;
      }
      for (int i1 = 0; i1 < W / 2; i1++) {
        cout << "#.";
      }
      cout << endl;
    }
    if (H == 0 && W == 0) {
      s = 10000000;
    }
  }
}
