import java.util.Scanner;

public class Main {
	static final boolean SHARP = true;
	static final boolean DOT = false;
	
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		while (true) {
			int h = sc.nextInt();
			int w = sc.nextInt();
			if (h == 0 || w == 0) {
				sc.close();
				break;
			}
			StringBuilder sb = new StringBuilder();
			boolean rowToggle = SHARP;
			for (int i = 0; i < h; i++) {
				boolean charToggle = rowToggle;
				for (int j = 0; j < w; j++) {
					char c = charToggle ? '#' : '.';
					sb.append(c);
					charToggle = charToggle ? DOT : SHARP;
				}
				sb.append("\n");
				rowToggle = rowToggle ? DOT : SHARP;
			}
			System.out.println(sb);
		}
	}
} import java.util.Scanner; Scanner java.util public class Main {
	static final boolean SHARP = true;
	static final boolean DOT = false;
	
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		while (true) {
			int h = sc.nextInt();
			int w = sc.nextInt();
			if (h == 0 || w == 0) {
				sc.close();
				break;
			}
			StringBuilder sb = new StringBuilder();
			boolean rowToggle = SHARP;
			for (int i = 0; i < h; i++) {
				boolean charToggle = rowToggle;
				for (int j = 0; j < w; j++) {
					char c = charToggle ? '#' : '.';
					sb.append(c);
					charToggle = charToggle ? DOT : SHARP;
				}
				sb.append("\n");
				rowToggle = rowToggle ? DOT : SHARP;
			}
			System.out.println(sb);
		}
	}
} Main static final boolean SHARP = true; SHARP true static final boolean DOT = false; DOT false public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		while (true) {
			int h = sc.nextInt();
			int w = sc.nextInt();
			if (h == 0 || w == 0) {
				sc.close();
				break;
			}
			StringBuilder sb = new StringBuilder();
			boolean rowToggle = SHARP;
			for (int i = 0; i < h; i++) {
				boolean charToggle = rowToggle;
				for (int j = 0; j < w; j++) {
					char c = charToggle ? '#' : '.';
					sb.append(c);
					charToggle = charToggle ? DOT : SHARP;
				}
				sb.append("\n");
				rowToggle = rowToggle ? DOT : SHARP;
			}
			System.out.println(sb);
		}
	} main {
		Scanner sc = new Scanner(System.in);
		while (true) {
			int h = sc.nextInt();
			int w = sc.nextInt();
			if (h == 0 || w == 0) {
				sc.close();
				break;
			}
			StringBuilder sb = new StringBuilder();
			boolean rowToggle = SHARP;
			for (int i = 0; i < h; i++) {
				boolean charToggle = rowToggle;
				for (int j = 0; j < w; j++) {
					char c = charToggle ? '#' : '.';
					sb.append(c);
					charToggle = charToggle ? DOT : SHARP;
				}
				sb.append("\n");
				rowToggle = rowToggle ? DOT : SHARP;
			}
			System.out.println(sb);
		}
	} Scanner sc = new Scanner(System.in); sc new Scanner(System.in) while (true) {
			int h = sc.nextInt();
			int w = sc.nextInt();
			if (h == 0 || w == 0) {
				sc.close();
				break;
			}
			StringBuilder sb = new StringBuilder();
			boolean rowToggle = SHARP;
			for (int i = 0; i < h; i++) {
				boolean charToggle = rowToggle;
				for (int j = 0; j < w; j++) {
					char c = charToggle ? '#' : '.';
					sb.append(c);
					charToggle = charToggle ? DOT : SHARP;
				}
				sb.append("\n");
				rowToggle = rowToggle ? DOT : SHARP;
			}
			System.out.println(sb);
		} true {
			int h = sc.nextInt();
			int w = sc.nextInt();
			if (h == 0 || w == 0) {
				sc.close();
				break;
			}
			StringBuilder sb = new StringBuilder();
			boolean rowToggle = SHARP;
			for (int i = 0; i < h; i++) {
				boolean charToggle = rowToggle;
				for (int j = 0; j < w; j++) {
					char c = charToggle ? '#' : '.';
					sb.append(c);
					charToggle = charToggle ? DOT : SHARP;
				}
				sb.append("\n");
				rowToggle = rowToggle ? DOT : SHARP;
			}
			System.out.println(sb);
		} int h = sc.nextInt(); h sc.nextInt() sc.nextInt sc int w = sc.nextInt(); w sc.nextInt() sc.nextInt sc if (h == 0 || w == 0) {
				sc.close();
				break;
			} h == 0 || w == 0 h == 0 h 0 w == 0 w 0 {
				sc.close();
				break;
			} sc.close() sc.close sc break; StringBuilder sb = new StringBuilder(); sb new StringBuilder() boolean rowToggle = SHARP; rowToggle SHARP for (int i = 0; i < h; i++) {
				boolean charToggle = rowToggle;
				for (int j = 0; j < w; j++) {
					char c = charToggle ? '#' : '.';
					sb.append(c);
					charToggle = charToggle ? DOT : SHARP;
				}
				sb.append("\n");
				rowToggle = rowToggle ? DOT : SHARP;
			} int i = 0; int i = 0; i 0 i < h i h i++ i++ i {
				boolean charToggle = rowToggle;
				for (int j = 0; j < w; j++) {
					char c = charToggle ? '#' : '.';
					sb.append(c);
					charToggle = charToggle ? DOT : SHARP;
				}
				sb.append("\n");
				rowToggle = rowToggle ? DOT : SHARP;
			} {
				boolean charToggle = rowToggle;
				for (int j = 0; j < w; j++) {
					char c = charToggle ? '#' : '.';
					sb.append(c);
					charToggle = charToggle ? DOT : SHARP;
				}
				sb.append("\n");
				rowToggle = rowToggle ? DOT : SHARP;
			} boolean charToggle = rowToggle; charToggle rowToggle for (int j = 0; j < w; j++) {
					char c = charToggle ? '#' : '.';
					sb.append(c);
					charToggle = charToggle ? DOT : SHARP;
				} int j = 0; int j = 0; j 0 j < w j w j++ j++ j {
					char c = charToggle ? '#' : '.';
					sb.append(c);
					charToggle = charToggle ? DOT : SHARP;
				} {
					char c = charToggle ? '#' : '.';
					sb.append(c);
					charToggle = charToggle ? DOT : SHARP;
				} char c = charToggle ? '#' : '.'; c charToggle ? '#' : '.' charToggle '#' '.' sb.append(c) sb.append sb c charToggle = charToggle ? DOT : SHARP charToggle charToggle ? DOT : SHARP charToggle DOT SHARP sb.append("\n") sb.append sb "\n" rowToggle = rowToggle ? DOT : SHARP rowToggle rowToggle ? DOT : SHARP rowToggle DOT SHARP System.out.println(sb) System.out.println System.out System System.out sb String[] args args public class Main {
	static final boolean SHARP = true;
	static final boolean DOT = false;
	
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		while (true) {
			int h = sc.nextInt();
			int w = sc.nextInt();
			if (h == 0 || w == 0) {
				sc.close();
				break;
			}
			StringBuilder sb = new StringBuilder();
			boolean rowToggle = SHARP;
			for (int i = 0; i < h; i++) {
				boolean charToggle = rowToggle;
				for (int j = 0; j < w; j++) {
					char c = charToggle ? '#' : '.';
					sb.append(c);
					charToggle = charToggle ? DOT : SHARP;
				}
				sb.append("\n");
				rowToggle = rowToggle ? DOT : SHARP;
			}
			System.out.println(sb);
		}
	}
} public class Main {
	static final boolean SHARP = true;
	static final boolean DOT = false;
	
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		while (true) {
			int h = sc.nextInt();
			int w = sc.nextInt();
			if (h == 0 || w == 0) {
				sc.close();
				break;
			}
			StringBuilder sb = new StringBuilder();
			boolean rowToggle = SHARP;
			for (int i = 0; i < h; i++) {
				boolean charToggle = rowToggle;
				for (int j = 0; j < w; j++) {
					char c = charToggle ? '#' : '.';
					sb.append(c);
					charToggle = charToggle ? DOT : SHARP;
				}
				sb.append("\n");
				rowToggle = rowToggle ? DOT : SHARP;
			}
			System.out.println(sb);
		}
	}
} Main
import java.util.Scanner;

public class Main {
	static final boolean SHARP = true;
	static final boolean DOT = false;
	
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		while (true) {
			int h = sc.nextInt();
			int w = sc.nextInt();
			if (h == 0 || w == 0) {
				sc.close();
				break;
			}
			StringBuilder sb = new StringBuilder();
			boolean rowToggle = SHARP;
			for (int i = 0; i < h; i++) {
				boolean charToggle = rowToggle;
				for (int j = 0; j < w; j++) {
					char c = charToggle ? '#' : '.';
					sb.append(c);
					charToggle = charToggle ? DOT : SHARP;
				}
				sb.append("\n");
				rowToggle = rowToggle ? DOT : SHARP;
			}
			System.out.println(sb);
		}
	}
}