#include <bits/stdc++.h>
using namespace std;
int main() {
  int H, W;
  cin >> H >> W;
  for (int y = 0; y < H; y++) {
    for (int x = 0; x < W; x++) {
      if (y % 2 == 0) {
        if (x % 2 == 0)
          cout << "#";
        else
          cout << ".";
      } else {
        if (x % 2 == 0)
          cout << ".";
        else
          cout << "#";
      }
      cout << endl;
    }
    cout << endl;
  }
  return 0;
}
