import java.util.Scanner;

public class Main {
	static int h, w;
	static Scanner sc = new Scanner(System.in);

	public static void main(String[] args) {
		input();
		while (h != 0 && w != 0){
			drawLine();
			input();
		}

	}
	static void drawLine () {
		String oddLine = makeOddLine(w);
		String evenLine = makeEvenLine(w);
		for (int i = 0; i < h; i++){
			if (i % 2 == 0) System.out.println(oddLine);
			else
				System.out.println(evenLine);
		}
		System.out.println();
	}
	static void input (){
		h = sc.nextInt();
		w = sc.nextInt();
	}

	static String makeOddLine(int n) {
		StringBuilder line = new StringBuilder();
		for (int i = 0; i < n; i++) {
			if (i % 2 == 0) {
				line.append("#");
			} else {
				line.append(".");
			}
		}
		return line.toString();
	}

	static String makeEvenLine(int n) {
		StringBuilder line = new StringBuilder();
		for (int i = 0; i < n; i++) {
			if (i % 2 == 0) {
				line.append(".");
			} else {
				line.append("#");
			}
		}
		return line.toString();
	}

} import java.util.Scanner; Scanner java.util public class Main {
	static int h, w;
	static Scanner sc = new Scanner(System.in);

	public static void main(String[] args) {
		input();
		while (h != 0 && w != 0){
			drawLine();
			input();
		}

	}
	static void drawLine () {
		String oddLine = makeOddLine(w);
		String evenLine = makeEvenLine(w);
		for (int i = 0; i < h; i++){
			if (i % 2 == 0) System.out.println(oddLine);
			else
				System.out.println(evenLine);
		}
		System.out.println();
	}
	static void input (){
		h = sc.nextInt();
		w = sc.nextInt();
	}

	static String makeOddLine(int n) {
		StringBuilder line = new StringBuilder();
		for (int i = 0; i < n; i++) {
			if (i % 2 == 0) {
				line.append("#");
			} else {
				line.append(".");
			}
		}
		return line.toString();
	}

	static String makeEvenLine(int n) {
		StringBuilder line = new StringBuilder();
		for (int i = 0; i < n; i++) {
			if (i % 2 == 0) {
				line.append(".");
			} else {
				line.append("#");
			}
		}
		return line.toString();
	}

} Main static int h h w; w static Scanner sc = new Scanner(System.in); sc new Scanner(System.in) public static void main(String[] args) {
		input();
		while (h != 0 && w != 0){
			drawLine();
			input();
		}

	} main {
		input();
		while (h != 0 && w != 0){
			drawLine();
			input();
		}

	} input() input while (h != 0 && w != 0){
			drawLine();
			input();
		} h != 0 && w != 0 h != 0 h 0 w != 0 w 0 {
			drawLine();
			input();
		} drawLine() drawLine input() input String[] args args static void drawLine () {
		String oddLine = makeOddLine(w);
		String evenLine = makeEvenLine(w);
		for (int i = 0; i < h; i++){
			if (i % 2 == 0) System.out.println(oddLine);
			else
				System.out.println(evenLine);
		}
		System.out.println();
	} drawLine {
		String oddLine = makeOddLine(w);
		String evenLine = makeEvenLine(w);
		for (int i = 0; i < h; i++){
			if (i % 2 == 0) System.out.println(oddLine);
			else
				System.out.println(evenLine);
		}
		System.out.println();
	} String oddLine = makeOddLine(w); oddLine makeOddLine(w) makeOddLine w String evenLine = makeEvenLine(w); evenLine makeEvenLine(w) makeEvenLine w for (int i = 0; i < h; i++){
			if (i % 2 == 0) System.out.println(oddLine);
			else
				System.out.println(evenLine);
		} int i = 0; int i = 0; i 0 i < h i h i++ i++ i {
			if (i % 2 == 0) System.out.println(oddLine);
			else
				System.out.println(evenLine);
		} {
			if (i % 2 == 0) System.out.println(oddLine);
			else
				System.out.println(evenLine);
		} if (i % 2 == 0) System.out.println(oddLine);
			else
				System.out.println(evenLine); i % 2 == 0 i % 2 i 2 0 System.out.println(oddLine) System.out.println System.out System System.out oddLine System.out.println(evenLine) System.out.println System.out System System.out evenLine System.out.println() System.out.println System.out System System.out static void input (){
		h = sc.nextInt();
		w = sc.nextInt();
	} input {
		h = sc.nextInt();
		w = sc.nextInt();
	} h = sc.nextInt() h sc.nextInt() sc.nextInt sc w = sc.nextInt() w sc.nextInt() sc.nextInt sc static String makeOddLine(int n) {
		StringBuilder line = new StringBuilder();
		for (int i = 0; i < n; i++) {
			if (i % 2 == 0) {
				line.append("#");
			} else {
				line.append(".");
			}
		}
		return line.toString();
	} makeOddLine {
		StringBuilder line = new StringBuilder();
		for (int i = 0; i < n; i++) {
			if (i % 2 == 0) {
				line.append("#");
			} else {
				line.append(".");
			}
		}
		return line.toString();
	} StringBuilder line = new StringBuilder(); line new StringBuilder() for (int i = 0; i < n; i++) {
			if (i % 2 == 0) {
				line.append("#");
			} else {
				line.append(".");
			}
		} int i = 0; int i = 0; i 0 i < n i n i++ i++ i {
			if (i % 2 == 0) {
				line.append("#");
			} else {
				line.append(".");
			}
		} {
			if (i % 2 == 0) {
				line.append("#");
			} else {
				line.append(".");
			}
		} if (i % 2 == 0) {
				line.append("#");
			} else {
				line.append(".");
			} i % 2 == 0 i % 2 i 2 0 {
				line.append("#");
			} line.append("#") line.append line "#" {
				line.append(".");
			} line.append(".") line.append line "." return line.toString(); line.toString() line.toString line int n n static String makeEvenLine(int n) {
		StringBuilder line = new StringBuilder();
		for (int i = 0; i < n; i++) {
			if (i % 2 == 0) {
				line.append(".");
			} else {
				line.append("#");
			}
		}
		return line.toString();
	} makeEvenLine {
		StringBuilder line = new StringBuilder();
		for (int i = 0; i < n; i++) {
			if (i % 2 == 0) {
				line.append(".");
			} else {
				line.append("#");
			}
		}
		return line.toString();
	} StringBuilder line = new StringBuilder(); line new StringBuilder() for (int i = 0; i < n; i++) {
			if (i % 2 == 0) {
				line.append(".");
			} else {
				line.append("#");
			}
		} int i = 0; int i = 0; i 0 i < n i n i++ i++ i {
			if (i % 2 == 0) {
				line.append(".");
			} else {
				line.append("#");
			}
		} {
			if (i % 2 == 0) {
				line.append(".");
			} else {
				line.append("#");
			}
		} if (i % 2 == 0) {
				line.append(".");
			} else {
				line.append("#");
			} i % 2 == 0 i % 2 i 2 0 {
				line.append(".");
			} line.append(".") line.append line "." {
				line.append("#");
			} line.append("#") line.append line "#" return line.toString(); line.toString() line.toString line int n n public class Main {
	static int h, w;
	static Scanner sc = new Scanner(System.in);

	public static void main(String[] args) {
		input();
		while (h != 0 && w != 0){
			drawLine();
			input();
		}

	}
	static void drawLine () {
		String oddLine = makeOddLine(w);
		String evenLine = makeEvenLine(w);
		for (int i = 0; i < h; i++){
			if (i % 2 == 0) System.out.println(oddLine);
			else
				System.out.println(evenLine);
		}
		System.out.println();
	}
	static void input (){
		h = sc.nextInt();
		w = sc.nextInt();
	}

	static String makeOddLine(int n) {
		StringBuilder line = new StringBuilder();
		for (int i = 0; i < n; i++) {
			if (i % 2 == 0) {
				line.append("#");
			} else {
				line.append(".");
			}
		}
		return line.toString();
	}

	static String makeEvenLine(int n) {
		StringBuilder line = new StringBuilder();
		for (int i = 0; i < n; i++) {
			if (i % 2 == 0) {
				line.append(".");
			} else {
				line.append("#");
			}
		}
		return line.toString();
	}

} public class Main {
	static int h, w;
	static Scanner sc = new Scanner(System.in);

	public static void main(String[] args) {
		input();
		while (h != 0 && w != 0){
			drawLine();
			input();
		}

	}
	static void drawLine () {
		String oddLine = makeOddLine(w);
		String evenLine = makeEvenLine(w);
		for (int i = 0; i < h; i++){
			if (i % 2 == 0) System.out.println(oddLine);
			else
				System.out.println(evenLine);
		}
		System.out.println();
	}
	static void input (){
		h = sc.nextInt();
		w = sc.nextInt();
	}

	static String makeOddLine(int n) {
		StringBuilder line = new StringBuilder();
		for (int i = 0; i < n; i++) {
			if (i % 2 == 0) {
				line.append("#");
			} else {
				line.append(".");
			}
		}
		return line.toString();
	}

	static String makeEvenLine(int n) {
		StringBuilder line = new StringBuilder();
		for (int i = 0; i < n; i++) {
			if (i % 2 == 0) {
				line.append(".");
			} else {
				line.append("#");
			}
		}
		return line.toString();
	}

} Main
import java.util.Scanner;

public class Main {
	static int h, w;
	static Scanner sc = new Scanner(System.in);

	public static void main(String[] args) {
		input();
		while (h != 0 && w != 0){
			drawLine();
			input();
		}

	}
	static void drawLine () {
		String oddLine = makeOddLine(w);
		String evenLine = makeEvenLine(w);
		for (int i = 0; i < h; i++){
			if (i % 2 == 0) System.out.println(oddLine);
			else
				System.out.println(evenLine);
		}
		System.out.println();
	}
	static void input (){
		h = sc.nextInt();
		w = sc.nextInt();
	}

	static String makeOddLine(int n) {
		StringBuilder line = new StringBuilder();
		for (int i = 0; i < n; i++) {
			if (i % 2 == 0) {
				line.append("#");
			} else {
				line.append(".");
			}
		}
		return line.toString();
	}

	static String makeEvenLine(int n) {
		StringBuilder line = new StringBuilder();
		for (int i = 0; i < n; i++) {
			if (i % 2 == 0) {
				line.append(".");
			} else {
				line.append("#");
			}
		}
		return line.toString();
	}

}