import java.util.Scanner;
import java.util.ArrayList;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        ArrayList<Integer> H = new ArrayList<Integer>();
        ArrayList<Integer> W = new ArrayList<Integer>();
        int tempH, tempW;

        while (true) {
            tempH = sc.nextInt();
            tempW = sc.nextInt();
            if (tempH == 0 && tempW == 0)
                break;

            H.add(tempH);
            W.add(tempW);
        }

        for (int k = 0; k < H.size(); k++) {
            for (int i = 0; i < H.get(k); i++) {
                for (int j = 0; j < W.get(k); j++) {
                    if ((i + j) % 2 == 0)
                        System.out.print("#");
                    else
                        System.out.print(".");
                }
                System.out.println();
            }
            System.out.println();
        }

        sc.close();
    }
} import java.util.Scanner; Scanner java.util import java.util.ArrayList; ArrayList java.util public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        ArrayList<Integer> H = new ArrayList<Integer>();
        ArrayList<Integer> W = new ArrayList<Integer>();
        int tempH, tempW;

        while (true) {
            tempH = sc.nextInt();
            tempW = sc.nextInt();
            if (tempH == 0 && tempW == 0)
                break;

            H.add(tempH);
            W.add(tempW);
        }

        for (int k = 0; k < H.size(); k++) {
            for (int i = 0; i < H.get(k); i++) {
                for (int j = 0; j < W.get(k); j++) {
                    if ((i + j) % 2 == 0)
                        System.out.print("#");
                    else
                        System.out.print(".");
                }
                System.out.println();
            }
            System.out.println();
        }

        sc.close();
    }
} Main public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        ArrayList<Integer> H = new ArrayList<Integer>();
        ArrayList<Integer> W = new ArrayList<Integer>();
        int tempH, tempW;

        while (true) {
            tempH = sc.nextInt();
            tempW = sc.nextInt();
            if (tempH == 0 && tempW == 0)
                break;

            H.add(tempH);
            W.add(tempW);
        }

        for (int k = 0; k < H.size(); k++) {
            for (int i = 0; i < H.get(k); i++) {
                for (int j = 0; j < W.get(k); j++) {
                    if ((i + j) % 2 == 0)
                        System.out.print("#");
                    else
                        System.out.print(".");
                }
                System.out.println();
            }
            System.out.println();
        }

        sc.close();
    } main {
        Scanner sc = new Scanner(System.in);
        ArrayList<Integer> H = new ArrayList<Integer>();
        ArrayList<Integer> W = new ArrayList<Integer>();
        int tempH, tempW;

        while (true) {
            tempH = sc.nextInt();
            tempW = sc.nextInt();
            if (tempH == 0 && tempW == 0)
                break;

            H.add(tempH);
            W.add(tempW);
        }

        for (int k = 0; k < H.size(); k++) {
            for (int i = 0; i < H.get(k); i++) {
                for (int j = 0; j < W.get(k); j++) {
                    if ((i + j) % 2 == 0)
                        System.out.print("#");
                    else
                        System.out.print(".");
                }
                System.out.println();
            }
            System.out.println();
        }

        sc.close();
    } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) ArrayList<Integer> H = new ArrayList<Integer>(); H new ArrayList<Integer>() ArrayList<Integer> W = new ArrayList<Integer>(); W new ArrayList<Integer>() int tempH tempH tempW; tempW while (true) {
            tempH = sc.nextInt();
            tempW = sc.nextInt();
            if (tempH == 0 && tempW == 0)
                break;

            H.add(tempH);
            W.add(tempW);
        } true {
            tempH = sc.nextInt();
            tempW = sc.nextInt();
            if (tempH == 0 && tempW == 0)
                break;

            H.add(tempH);
            W.add(tempW);
        } tempH = sc.nextInt() tempH sc.nextInt() sc.nextInt sc tempW = sc.nextInt() tempW sc.nextInt() sc.nextInt sc if (tempH == 0 && tempW == 0)
                break; tempH == 0 && tempW == 0 tempH == 0 tempH 0 tempW == 0 tempW 0 break; H.add(tempH) H.add H tempH W.add(tempW) W.add W tempW for (int k = 0; k < H.size(); k++) {
            for (int i = 0; i < H.get(k); i++) {
                for (int j = 0; j < W.get(k); j++) {
                    if ((i + j) % 2 == 0)
                        System.out.print("#");
                    else
                        System.out.print(".");
                }
                System.out.println();
            }
            System.out.println();
        } int k = 0; int k = 0; k 0 k < H.size() k H.size() H.size H k++ k++ k {
            for (int i = 0; i < H.get(k); i++) {
                for (int j = 0; j < W.get(k); j++) {
                    if ((i + j) % 2 == 0)
                        System.out.print("#");
                    else
                        System.out.print(".");
                }
                System.out.println();
            }
            System.out.println();
        } {
            for (int i = 0; i < H.get(k); i++) {
                for (int j = 0; j < W.get(k); j++) {
                    if ((i + j) % 2 == 0)
                        System.out.print("#");
                    else
                        System.out.print(".");
                }
                System.out.println();
            }
            System.out.println();
        } for (int i = 0; i < H.get(k); i++) {
                for (int j = 0; j < W.get(k); j++) {
                    if ((i + j) % 2 == 0)
                        System.out.print("#");
                    else
                        System.out.print(".");
                }
                System.out.println();
            } int i = 0; int i = 0; i 0 i < H.get(k) i H.get(k) H.get H k i++ i++ i {
                for (int j = 0; j < W.get(k); j++) {
                    if ((i + j) % 2 == 0)
                        System.out.print("#");
                    else
                        System.out.print(".");
                }
                System.out.println();
            } {
                for (int j = 0; j < W.get(k); j++) {
                    if ((i + j) % 2 == 0)
                        System.out.print("#");
                    else
                        System.out.print(".");
                }
                System.out.println();
            } for (int j = 0; j < W.get(k); j++) {
                    if ((i + j) % 2 == 0)
                        System.out.print("#");
                    else
                        System.out.print(".");
                } int j = 0; int j = 0; j 0 j < W.get(k) j W.get(k) W.get W k j++ j++ j {
                    if ((i + j) % 2 == 0)
                        System.out.print("#");
                    else
                        System.out.print(".");
                } {
                    if ((i + j) % 2 == 0)
                        System.out.print("#");
                    else
                        System.out.print(".");
                } if ((i + j) % 2 == 0)
                        System.out.print("#");
                    else
                        System.out.print("."); (i + j) % 2 == 0 (i + j) % 2 (i + j) i j 2 0 System.out.print("#") System.out.print System.out System System.out "#" System.out.print(".") System.out.print System.out System System.out "." System.out.println() System.out.println System.out System System.out System.out.println() System.out.println System.out System System.out sc.close() sc.close sc String[] args args public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        ArrayList<Integer> H = new ArrayList<Integer>();
        ArrayList<Integer> W = new ArrayList<Integer>();
        int tempH, tempW;

        while (true) {
            tempH = sc.nextInt();
            tempW = sc.nextInt();
            if (tempH == 0 && tempW == 0)
                break;

            H.add(tempH);
            W.add(tempW);
        }

        for (int k = 0; k < H.size(); k++) {
            for (int i = 0; i < H.get(k); i++) {
                for (int j = 0; j < W.get(k); j++) {
                    if ((i + j) % 2 == 0)
                        System.out.print("#");
                    else
                        System.out.print(".");
                }
                System.out.println();
            }
            System.out.println();
        }

        sc.close();
    }
} public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        ArrayList<Integer> H = new ArrayList<Integer>();
        ArrayList<Integer> W = new ArrayList<Integer>();
        int tempH, tempW;

        while (true) {
            tempH = sc.nextInt();
            tempW = sc.nextInt();
            if (tempH == 0 && tempW == 0)
                break;

            H.add(tempH);
            W.add(tempW);
        }

        for (int k = 0; k < H.size(); k++) {
            for (int i = 0; i < H.get(k); i++) {
                for (int j = 0; j < W.get(k); j++) {
                    if ((i + j) % 2 == 0)
                        System.out.print("#");
                    else
                        System.out.print(".");
                }
                System.out.println();
            }
            System.out.println();
        }

        sc.close();
    }
} Main
import java.util.Scanner;
import java.util.ArrayList;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        ArrayList<Integer> H = new ArrayList<Integer>();
        ArrayList<Integer> W = new ArrayList<Integer>();
        int tempH, tempW;

        while (true) {
            tempH = sc.nextInt();
            tempW = sc.nextInt();
            if (tempH == 0 && tempW == 0)
                break;

            H.add(tempH);
            W.add(tempW);
        }

        for (int k = 0; k < H.size(); k++) {
            for (int i = 0; i < H.get(k); i++) {
                for (int j = 0; j < W.get(k); j++) {
                    if ((i + j) % 2 == 0)
                        System.out.print("#");
                    else
                        System.out.print(".");
                }
                System.out.println();
            }
            System.out.println();
        }

        sc.close();
    }
}
