#include <bits/stdc++.h>
using namespace std;
int main() {
  int x, y, z;
  cin >> x >> y;
  for (int a = 1; a <= x; a++) {
    for (int b = 1; b <= y; b++) {
      if ((a + b) % 2 == 0) {
        cout << "#";
      } else {
        cout << ".";
      }
    }
    cout << endl;
  }
}
