import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.ArrayList;

public class Main {

	public static void main(String[] args) {

		//?????£?????????
		int numH = 0;
		int numW = 0;

		String cell = "#";
		String con = ".";

		String[] NumWork;

		try {
			//??\????????????
			BufferedReader br = new BufferedReader(new InputStreamReader(System.in));

			while (true) {
				String line = br.readLine();

				if (line != null) {

					//??°??£?????´??°?????????
					NumWork = line.split(" ", 0);

					//??´??°?????°??????
					ArrayList<Integer> NumList = new ArrayList<Integer>();

					for (int i = 0; i < NumWork.length; i++) {
						NumList.add(Integer.parseInt(NumWork[i]));
					}
					numH = NumList.get(0);
					numW = NumList.get(1);

					// ????????¨(?????????????????????)
					String outputStr = "";

					//??????????????????
					if (numH != 0 || numW != 0) {

						//????????¢?????????

						//????????????
						for (int i = 1; i <= numH; i++) {
							for (int j = 1; j <= numW; j++) {

								// ?\???°??????(#.#.)
								if ((i % 2) == 1){
									//??????????????????
									if((j % 2) == 1){
										outputStr += cell;
									}else{
									outputStr += con;
									}
								//??¶??°??????(.#.#)
								} else {
									//??????????????????
									if((j % 2) == 1){
										outputStr += con;
									}else{
									outputStr += cell;
									}
								}
							}
							//?????£???????????????
							System.out.println(outputStr);
							outputStr = "";
						}
						System.out.println("");

					}else{
						break;
					}
				}else{
					break;
				}

			}
		} catch (IOException e) {
			System.out.println(e);
		}

	}

}
/tmp/hf-datasets-cache/medium/datasets/42704881117311-config-parquet-and-info-qiankunmu-Project_CodeNet-896c9d36/hub/datasets--qiankunmu--Project_CodeNet_Python800_and_Java250/snapshots/c899fde44a77ba1cc14973ed3de064e4ff3aadc7/Project_CodeNet_Java250.tar.gz