#include <bits/stdc++.h>
using namespace std;
int main() {
  int H, W;
  for (int a = 0; a < 10000; a++) {
    cin >> H >> W;
    for (int b = 0; b < H; b++) {
      for (int c = 0; c < W; c++) {
        if ((b % 2 == 0 && c % 2 == 0) || (b % 2 == 1 && c % 2 == 1)) {
          cout << "#";
        } else {
          cout << ".";
        }
      }
      cout << endl;
    }
    cout << endl;
  }
}
