import java.util.Scanner;

public class Main {
    public static void main(String[] args) {

        Scanner sc = new Scanner(System.in);
        int[] H, W;
        int i, j, k, count;

        H = new int[100000];
        W = new int[100000];

        i=0;
        while(true){
            if(i == 100000){break;}

            H[i] = sc.nextInt();
            W[i] = sc.nextInt();

            if(H[i] == 0 && W[i] == 0){break;}
            i++;
        }
        count = i;

        for(k=0;k<count;k++){
            for(i=0;i<H[k];i++){
                for(j=0;j<W[k];j++){
                    if(i%2==0){
                        if(j%2==0){
                            System.out.print("#");
                        }else{
                            System.out.print(".");
                        }
                    }else{
                        if(j%2==0){
                            System.out.print(".");
                        }else{
                            System.out.print("#");
                        }
                    }

                }
                System.out.println();
            }
            System.out.println();
        }
    }
}
 import java.util.Scanner; Scanner java.util public class Main {
    public static void main(String[] args) {

        Scanner sc = new Scanner(System.in);
        int[] H, W;
        int i, j, k, count;

        H = new int[100000];
        W = new int[100000];

        i=0;
        while(true){
            if(i == 100000){break;}

            H[i] = sc.nextInt();
            W[i] = sc.nextInt();

            if(H[i] == 0 && W[i] == 0){break;}
            i++;
        }
        count = i;

        for(k=0;k<count;k++){
            for(i=0;i<H[k];i++){
                for(j=0;j<W[k];j++){
                    if(i%2==0){
                        if(j%2==0){
                            System.out.print("#");
                        }else{
                            System.out.print(".");
                        }
                    }else{
                        if(j%2==0){
                            System.out.print(".");
                        }else{
                            System.out.print("#");
                        }
                    }

                }
                System.out.println();
            }
            System.out.println();
        }
    }
} Main public static void main(String[] args) {

        Scanner sc = new Scanner(System.in);
        int[] H, W;
        int i, j, k, count;

        H = new int[100000];
        W = new int[100000];

        i=0;
        while(true){
            if(i == 100000){break;}

            H[i] = sc.nextInt();
            W[i] = sc.nextInt();

            if(H[i] == 0 && W[i] == 0){break;}
            i++;
        }
        count = i;

        for(k=0;k<count;k++){
            for(i=0;i<H[k];i++){
                for(j=0;j<W[k];j++){
                    if(i%2==0){
                        if(j%2==0){
                            System.out.print("#");
                        }else{
                            System.out.print(".");
                        }
                    }else{
                        if(j%2==0){
                            System.out.print(".");
                        }else{
                            System.out.print("#");
                        }
                    }

                }
                System.out.println();
            }
            System.out.println();
        }
    } main {

        Scanner sc = new Scanner(System.in);
        int[] H, W;
        int i, j, k, count;

        H = new int[100000];
        W = new int[100000];

        i=0;
        while(true){
            if(i == 100000){break;}

            H[i] = sc.nextInt();
            W[i] = sc.nextInt();

            if(H[i] == 0 && W[i] == 0){break;}
            i++;
        }
        count = i;

        for(k=0;k<count;k++){
            for(i=0;i<H[k];i++){
                for(j=0;j<W[k];j++){
                    if(i%2==0){
                        if(j%2==0){
                            System.out.print("#");
                        }else{
                            System.out.print(".");
                        }
                    }else{
                        if(j%2==0){
                            System.out.print(".");
                        }else{
                            System.out.print("#");
                        }
                    }

                }
                System.out.println();
            }
            System.out.println();
        }
    } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) int[] H H W; W int i i j j k k count; count H = new int[100000] H new int[100000] 100000 W = new int[100000] W new int[100000] 100000 i=0 i 0 while(true){
            if(i == 100000){break;}

            H[i] = sc.nextInt();
            W[i] = sc.nextInt();

            if(H[i] == 0 && W[i] == 0){break;}
            i++;
        } true {
            if(i == 100000){break;}

            H[i] = sc.nextInt();
            W[i] = sc.nextInt();

            if(H[i] == 0 && W[i] == 0){break;}
            i++;
        } if(i == 100000){break;} i == 100000 i 100000 {break;} break; H[i] = sc.nextInt() H[i] H i sc.nextInt() sc.nextInt sc W[i] = sc.nextInt() W[i] W i sc.nextInt() sc.nextInt sc if(H[i] == 0 && W[i] == 0){break;} H[i] == 0 && W[i] == 0 H[i] == 0 H[i] H i 0 W[i] == 0 W[i] W i 0 {break;} break; i++ i count = i count i for(k=0;k<count;k++){
            for(i=0;i<H[k];i++){
                for(j=0;j<W[k];j++){
                    if(i%2==0){
                        if(j%2==0){
                            System.out.print("#");
                        }else{
                            System.out.print(".");
                        }
                    }else{
                        if(j%2==0){
                            System.out.print(".");
                        }else{
                            System.out.print("#");
                        }
                    }

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

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

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

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

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

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

                } j=0; j=0 j 0 j<W[k] j W[k] W k j++ j++ j {
                    if(i%2==0){
                        if(j%2==0){
                            System.out.print("#");
                        }else{
                            System.out.print(".");
                        }
                    }else{
                        if(j%2==0){
                            System.out.print(".");
                        }else{
                            System.out.print("#");
                        }
                    }

                } {
                    if(i%2==0){
                        if(j%2==0){
                            System.out.print("#");
                        }else{
                            System.out.print(".");
                        }
                    }else{
                        if(j%2==0){
                            System.out.print(".");
                        }else{
                            System.out.print("#");
                        }
                    }

                } if(i%2==0){
                        if(j%2==0){
                            System.out.print("#");
                        }else{
                            System.out.print(".");
                        }
                    }else{
                        if(j%2==0){
                            System.out.print(".");
                        }else{
                            System.out.print("#");
                        }
                    } i%2==0 i%2 i 2 0 {
                        if(j%2==0){
                            System.out.print("#");
                        }else{
                            System.out.print(".");
                        }
                    } if(j%2==0){
                            System.out.print("#");
                        }else{
                            System.out.print(".");
                        } j%2==0 j%2 j 2 0 {
                            System.out.print("#");
                        } System.out.print("#") System.out.print System.out System System.out "#" {
                            System.out.print(".");
                        } System.out.print(".") System.out.print System.out System System.out "." {
                        if(j%2==0){
                            System.out.print(".");
                        }else{
                            System.out.print("#");
                        }
                    } if(j%2==0){
                            System.out.print(".");
                        }else{
                            System.out.print("#");
                        } j%2==0 j%2 j 2 0 {
                            System.out.print(".");
                        } System.out.print(".") System.out.print System.out System System.out "." {
                            System.out.print("#");
                        } 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 String[] args args public class Main {
    public static void main(String[] args) {

        Scanner sc = new Scanner(System.in);
        int[] H, W;
        int i, j, k, count;

        H = new int[100000];
        W = new int[100000];

        i=0;
        while(true){
            if(i == 100000){break;}

            H[i] = sc.nextInt();
            W[i] = sc.nextInt();

            if(H[i] == 0 && W[i] == 0){break;}
            i++;
        }
        count = i;

        for(k=0;k<count;k++){
            for(i=0;i<H[k];i++){
                for(j=0;j<W[k];j++){
                    if(i%2==0){
                        if(j%2==0){
                            System.out.print("#");
                        }else{
                            System.out.print(".");
                        }
                    }else{
                        if(j%2==0){
                            System.out.print(".");
                        }else{
                            System.out.print("#");
                        }
                    }

                }
                System.out.println();
            }
            System.out.println();
        }
    }
} public class Main {
    public static void main(String[] args) {

        Scanner sc = new Scanner(System.in);
        int[] H, W;
        int i, j, k, count;

        H = new int[100000];
        W = new int[100000];

        i=0;
        while(true){
            if(i == 100000){break;}

            H[i] = sc.nextInt();
            W[i] = sc.nextInt();

            if(H[i] == 0 && W[i] == 0){break;}
            i++;
        }
        count = i;

        for(k=0;k<count;k++){
            for(i=0;i<H[k];i++){
                for(j=0;j<W[k];j++){
                    if(i%2==0){
                        if(j%2==0){
                            System.out.print("#");
                        }else{
                            System.out.print(".");
                        }
                    }else{
                        if(j%2==0){
                            System.out.print(".");
                        }else{
                            System.out.print("#");
                        }
                    }

                }
                System.out.println();
            }
            System.out.println();
        }
    }
} Main
import java.util.Scanner;

public class Main {
    public static void main(String[] args) {

        Scanner sc = new Scanner(System.in);
        int[] H, W;
        int i, j, k, count;

        H = new int[100000];
        W = new int[100000];

        i=0;
        while(true){
            if(i == 100000){break;}

            H[i] = sc.nextInt();
            W[i] = sc.nextInt();

            if(H[i] == 0 && W[i] == 0){break;}
            i++;
        }
        count = i;

        for(k=0;k<count;k++){
            for(i=0;i<H[k];i++){
                for(j=0;j<W[k];j++){
                    if(i%2==0){
                        if(j%2==0){
                            System.out.print("#");
                        }else{
                            System.out.print(".");
                        }
                    }else{
                        if(j%2==0){
                            System.out.print(".");
                        }else{
                            System.out.print("#");
                        }
                    }

                }
                System.out.println();
            }
            System.out.println();
        }
    }
}

