import java.io.BufferedReader;
import java.io.InputStreamReader;

public class Main {
	private static final String BR = System.getProperty("line.separator");

	public static void main(String[] args) {
		try {
			BufferedReader br = new BufferedReader(new InputStreamReader(
					System.in));

			StringBuilder s = new StringBuilder();
			String[] strArray;
			String line = br.readLine();

			while (line.equals("0 0") == false) {
				strArray = line.split("\\s");
				for (int i = 0; i < Integer.parseInt(strArray[0]); i++) {
					for (int j = 0; j < Integer.parseInt(strArray[1]); j++) {
						if (i % 2 == 0) {
							if (j % 2 == 0) {
								s.append("#");
							} else {
								s.append(".");
							}
						} else {
							if (j % 2 == 0) {
								s.append(".");
							} else {
								s.append("#");
							}
						}
					}
					s.append(BR);
				}
				System.out.println(s);
				s.delete(0, s.length());
				line = br.readLine();
			}
			br.close();
		} catch (Exception e) {
			System.err.println(e);
		}
	}
} import java.io.BufferedReader; BufferedReader java.io import java.io.InputStreamReader; InputStreamReader java.io public class Main {
	private static final String BR = System.getProperty("line.separator");

	public static void main(String[] args) {
		try {
			BufferedReader br = new BufferedReader(new InputStreamReader(
					System.in));

			StringBuilder s = new StringBuilder();
			String[] strArray;
			String line = br.readLine();

			while (line.equals("0 0") == false) {
				strArray = line.split("\\s");
				for (int i = 0; i < Integer.parseInt(strArray[0]); i++) {
					for (int j = 0; j < Integer.parseInt(strArray[1]); j++) {
						if (i % 2 == 0) {
							if (j % 2 == 0) {
								s.append("#");
							} else {
								s.append(".");
							}
						} else {
							if (j % 2 == 0) {
								s.append(".");
							} else {
								s.append("#");
							}
						}
					}
					s.append(BR);
				}
				System.out.println(s);
				s.delete(0, s.length());
				line = br.readLine();
			}
			br.close();
		} catch (Exception e) {
			System.err.println(e);
		}
	}
} Main private static final String BR = System.getProperty("line.separator"); BR System.getProperty("line.separator") System.getProperty System "line.separator" public static void main(String[] args) {
		try {
			BufferedReader br = new BufferedReader(new InputStreamReader(
					System.in));

			StringBuilder s = new StringBuilder();
			String[] strArray;
			String line = br.readLine();

			while (line.equals("0 0") == false) {
				strArray = line.split("\\s");
				for (int i = 0; i < Integer.parseInt(strArray[0]); i++) {
					for (int j = 0; j < Integer.parseInt(strArray[1]); j++) {
						if (i % 2 == 0) {
							if (j % 2 == 0) {
								s.append("#");
							} else {
								s.append(".");
							}
						} else {
							if (j % 2 == 0) {
								s.append(".");
							} else {
								s.append("#");
							}
						}
					}
					s.append(BR);
				}
				System.out.println(s);
				s.delete(0, s.length());
				line = br.readLine();
			}
			br.close();
		} catch (Exception e) {
			System.err.println(e);
		}
	} main {
		try {
			BufferedReader br = new BufferedReader(new InputStreamReader(
					System.in));

			StringBuilder s = new StringBuilder();
			String[] strArray;
			String line = br.readLine();

			while (line.equals("0 0") == false) {
				strArray = line.split("\\s");
				for (int i = 0; i < Integer.parseInt(strArray[0]); i++) {
					for (int j = 0; j < Integer.parseInt(strArray[1]); j++) {
						if (i % 2 == 0) {
							if (j % 2 == 0) {
								s.append("#");
							} else {
								s.append(".");
							}
						} else {
							if (j % 2 == 0) {
								s.append(".");
							} else {
								s.append("#");
							}
						}
					}
					s.append(BR);
				}
				System.out.println(s);
				s.delete(0, s.length());
				line = br.readLine();
			}
			br.close();
		} catch (Exception e) {
			System.err.println(e);
		}
	} try {
			BufferedReader br = new BufferedReader(new InputStreamReader(
					System.in));

			StringBuilder s = new StringBuilder();
			String[] strArray;
			String line = br.readLine();

			while (line.equals("0 0") == false) {
				strArray = line.split("\\s");
				for (int i = 0; i < Integer.parseInt(strArray[0]); i++) {
					for (int j = 0; j < Integer.parseInt(strArray[1]); j++) {
						if (i % 2 == 0) {
							if (j % 2 == 0) {
								s.append("#");
							} else {
								s.append(".");
							}
						} else {
							if (j % 2 == 0) {
								s.append(".");
							} else {
								s.append("#");
							}
						}
					}
					s.append(BR);
				}
				System.out.println(s);
				s.delete(0, s.length());
				line = br.readLine();
			}
			br.close();
		} catch (Exception e) {
			System.err.println(e);
		} catch (Exception e) {
			System.err.println(e);
		} Exception e {
			System.err.println(e);
		} System.err.println(e) System.err.println System.err System System.err e {
			BufferedReader br = new BufferedReader(new InputStreamReader(
					System.in));

			StringBuilder s = new StringBuilder();
			String[] strArray;
			String line = br.readLine();

			while (line.equals("0 0") == false) {
				strArray = line.split("\\s");
				for (int i = 0; i < Integer.parseInt(strArray[0]); i++) {
					for (int j = 0; j < Integer.parseInt(strArray[1]); j++) {
						if (i % 2 == 0) {
							if (j % 2 == 0) {
								s.append("#");
							} else {
								s.append(".");
							}
						} else {
							if (j % 2 == 0) {
								s.append(".");
							} else {
								s.append("#");
							}
						}
					}
					s.append(BR);
				}
				System.out.println(s);
				s.delete(0, s.length());
				line = br.readLine();
			}
			br.close();
		} BufferedReader br = new BufferedReader(new InputStreamReader(
					System.in)); br new BufferedReader(new InputStreamReader(
					System.in)) StringBuilder s = new StringBuilder(); s new StringBuilder() String[] strArray; strArray String line = br.readLine(); line br.readLine() br.readLine br while (line.equals("0 0") == false) {
				strArray = line.split("\\s");
				for (int i = 0; i < Integer.parseInt(strArray[0]); i++) {
					for (int j = 0; j < Integer.parseInt(strArray[1]); j++) {
						if (i % 2 == 0) {
							if (j % 2 == 0) {
								s.append("#");
							} else {
								s.append(".");
							}
						} else {
							if (j % 2 == 0) {
								s.append(".");
							} else {
								s.append("#");
							}
						}
					}
					s.append(BR);
				}
				System.out.println(s);
				s.delete(0, s.length());
				line = br.readLine();
			} line.equals("0 0") == false line.equals("0 0") line.equals line "0 0" false {
				strArray = line.split("\\s");
				for (int i = 0; i < Integer.parseInt(strArray[0]); i++) {
					for (int j = 0; j < Integer.parseInt(strArray[1]); j++) {
						if (i % 2 == 0) {
							if (j % 2 == 0) {
								s.append("#");
							} else {
								s.append(".");
							}
						} else {
							if (j % 2 == 0) {
								s.append(".");
							} else {
								s.append("#");
							}
						}
					}
					s.append(BR);
				}
				System.out.println(s);
				s.delete(0, s.length());
				line = br.readLine();
			} strArray = line.split("\\s") strArray line.split("\\s") line.split line "\\s" for (int i = 0; i < Integer.parseInt(strArray[0]); i++) {
					for (int j = 0; j < Integer.parseInt(strArray[1]); j++) {
						if (i % 2 == 0) {
							if (j % 2 == 0) {
								s.append("#");
							} else {
								s.append(".");
							}
						} else {
							if (j % 2 == 0) {
								s.append(".");
							} else {
								s.append("#");
							}
						}
					}
					s.append(BR);
				} int i = 0; int i = 0; i 0 i < Integer.parseInt(strArray[0]) i Integer.parseInt(strArray[0]) Integer.parseInt Integer strArray[0] strArray 0 i++ i++ i {
					for (int j = 0; j < Integer.parseInt(strArray[1]); j++) {
						if (i % 2 == 0) {
							if (j % 2 == 0) {
								s.append("#");
							} else {
								s.append(".");
							}
						} else {
							if (j % 2 == 0) {
								s.append(".");
							} else {
								s.append("#");
							}
						}
					}
					s.append(BR);
				} {
					for (int j = 0; j < Integer.parseInt(strArray[1]); j++) {
						if (i % 2 == 0) {
							if (j % 2 == 0) {
								s.append("#");
							} else {
								s.append(".");
							}
						} else {
							if (j % 2 == 0) {
								s.append(".");
							} else {
								s.append("#");
							}
						}
					}
					s.append(BR);
				} for (int j = 0; j < Integer.parseInt(strArray[1]); j++) {
						if (i % 2 == 0) {
							if (j % 2 == 0) {
								s.append("#");
							} else {
								s.append(".");
							}
						} else {
							if (j % 2 == 0) {
								s.append(".");
							} else {
								s.append("#");
							}
						}
					} int j = 0; int j = 0; j 0 j < Integer.parseInt(strArray[1]) j Integer.parseInt(strArray[1]) Integer.parseInt Integer strArray[1] strArray 1 j++ j++ j {
						if (i % 2 == 0) {
							if (j % 2 == 0) {
								s.append("#");
							} else {
								s.append(".");
							}
						} else {
							if (j % 2 == 0) {
								s.append(".");
							} else {
								s.append("#");
							}
						}
					} {
						if (i % 2 == 0) {
							if (j % 2 == 0) {
								s.append("#");
							} else {
								s.append(".");
							}
						} else {
							if (j % 2 == 0) {
								s.append(".");
							} else {
								s.append("#");
							}
						}
					} if (i % 2 == 0) {
							if (j % 2 == 0) {
								s.append("#");
							} else {
								s.append(".");
							}
						} else {
							if (j % 2 == 0) {
								s.append(".");
							} else {
								s.append("#");
							}
						} i % 2 == 0 i % 2 i 2 0 {
							if (j % 2 == 0) {
								s.append("#");
							} else {
								s.append(".");
							}
						} if (j % 2 == 0) {
								s.append("#");
							} else {
								s.append(".");
							} j % 2 == 0 j % 2 j 2 0 {
								s.append("#");
							} s.append("#") s.append s "#" {
								s.append(".");
							} s.append(".") s.append s "." {
							if (j % 2 == 0) {
								s.append(".");
							} else {
								s.append("#");
							}
						} if (j % 2 == 0) {
								s.append(".");
							} else {
								s.append("#");
							} j % 2 == 0 j % 2 j 2 0 {
								s.append(".");
							} s.append(".") s.append s "." {
								s.append("#");
							} s.append("#") s.append s "#" s.append(BR) s.append s BR System.out.println(s) System.out.println System.out System System.out s s.delete(0, s.length()) s.delete s 0 s.length() s.length s line = br.readLine() line br.readLine() br.readLine br br.close() br.close br String[] args args public class Main {
	private static final String BR = System.getProperty("line.separator");

	public static void main(String[] args) {
		try {
			BufferedReader br = new BufferedReader(new InputStreamReader(
					System.in));

			StringBuilder s = new StringBuilder();
			String[] strArray;
			String line = br.readLine();

			while (line.equals("0 0") == false) {
				strArray = line.split("\\s");
				for (int i = 0; i < Integer.parseInt(strArray[0]); i++) {
					for (int j = 0; j < Integer.parseInt(strArray[1]); j++) {
						if (i % 2 == 0) {
							if (j % 2 == 0) {
								s.append("#");
							} else {
								s.append(".");
							}
						} else {
							if (j % 2 == 0) {
								s.append(".");
							} else {
								s.append("#");
							}
						}
					}
					s.append(BR);
				}
				System.out.println(s);
				s.delete(0, s.length());
				line = br.readLine();
			}
			br.close();
		} catch (Exception e) {
			System.err.println(e);
		}
	}
} public class Main {
	private static final String BR = System.getProperty("line.separator");

	public static void main(String[] args) {
		try {
			BufferedReader br = new BufferedReader(new InputStreamReader(
					System.in));

			StringBuilder s = new StringBuilder();
			String[] strArray;
			String line = br.readLine();

			while (line.equals("0 0") == false) {
				strArray = line.split("\\s");
				for (int i = 0; i < Integer.parseInt(strArray[0]); i++) {
					for (int j = 0; j < Integer.parseInt(strArray[1]); j++) {
						if (i % 2 == 0) {
							if (j % 2 == 0) {
								s.append("#");
							} else {
								s.append(".");
							}
						} else {
							if (j % 2 == 0) {
								s.append(".");
							} else {
								s.append("#");
							}
						}
					}
					s.append(BR);
				}
				System.out.println(s);
				s.delete(0, s.length());
				line = br.readLine();
			}
			br.close();
		} catch (Exception e) {
			System.err.println(e);
		}
	}
} Main
import java.io.BufferedReader;
import java.io.InputStreamReader;

public class Main {
	private static final String BR = System.getProperty("line.separator");

	public static void main(String[] args) {
		try {
			BufferedReader br = new BufferedReader(new InputStreamReader(
					System.in));

			StringBuilder s = new StringBuilder();
			String[] strArray;
			String line = br.readLine();

			while (line.equals("0 0") == false) {
				strArray = line.split("\\s");
				for (int i = 0; i < Integer.parseInt(strArray[0]); i++) {
					for (int j = 0; j < Integer.parseInt(strArray[1]); j++) {
						if (i % 2 == 0) {
							if (j % 2 == 0) {
								s.append("#");
							} else {
								s.append(".");
							}
						} else {
							if (j % 2 == 0) {
								s.append(".");
							} else {
								s.append("#");
							}
						}
					}
					s.append(BR);
				}
				System.out.println(s);
				s.delete(0, s.length());
				line = br.readLine();
			}
			br.close();
		} catch (Exception e) {
			System.err.println(e);
		}
	}
}