#include <iostream>
using namespace std;

int main() {
	int H, W, x,y;
	const char a[300];
	const char b[300];
	cin >> H >> W;
	for (int i = 0; i < 150; i++) {
		a[i * 2] = "#";
		a[i * 2 + 1] = ".";
		b[i * 2] = ".";
		b[i * 2 + 1] = "#";
	}
	x = W / 2;
	for (int j = 0; j < x; j++) {
		for (int k = 0; k < W; k++) {
			cout << a[k];
		}
		cout << endl;
		for (int l = 0; l < W; l++) {
			cout << b[l];
		}
		cout << endl;
	}
	if (W % 2 == 1) {
		for (int m = 0; m < W; m++) {
			cout << a[m];
		}
	}
	return 0;
	}