#include <bits/stdc++.h>
using namespace std;
int main() {
  int height, weight;
  scanf("%d %d", &height, &weight);
  for (int i = 1; i <= height; i++) {
    for (int j = 1; j <= weight; j++) {
      if ((i + j) % 2 == 0) {
        cout << '#';
      } else {
        cout << '.';
      }
      if (j == weight) cout << '\n';
    }
    if (i == height) cout << '\n';
  }
}
