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

public class Main {
    public static void main(String[] args) throws Exception {
        // Here your code !
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        while(true) {
            String line = br.readLine();
            String[] line2 = line.split(" ");
            if(Integer.parseInt(line2[0]) == 0)
                if(Integer.parseInt(line2[1]) == 0)
                    break;
            print(Integer.parseInt(line2[0]),Integer.parseInt(line2[1]));
        }
    }
    static void print(int h,int w) {
        for(int i=0;i < h;i++) {
            for(int j = 0; j < w ; 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.io.BufferedReader; BufferedReader java.io import java.io.InputStreamReader; InputStreamReader java.io public class Main {
    public static void main(String[] args) throws Exception {
        // Here your code !
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        while(true) {
            String line = br.readLine();
            String[] line2 = line.split(" ");
            if(Integer.parseInt(line2[0]) == 0)
                if(Integer.parseInt(line2[1]) == 0)
                    break;
            print(Integer.parseInt(line2[0]),Integer.parseInt(line2[1]));
        }
    }
    static void print(int h,int w) {
        for(int i=0;i < h;i++) {
            for(int j = 0; j < w ; 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) throws Exception {
        // Here your code !
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        while(true) {
            String line = br.readLine();
            String[] line2 = line.split(" ");
            if(Integer.parseInt(line2[0]) == 0)
                if(Integer.parseInt(line2[1]) == 0)
                    break;
            print(Integer.parseInt(line2[0]),Integer.parseInt(line2[1]));
        }
    } main {
        // Here your code !
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        while(true) {
            String line = br.readLine();
            String[] line2 = line.split(" ");
            if(Integer.parseInt(line2[0]) == 0)
                if(Integer.parseInt(line2[1]) == 0)
                    break;
            print(Integer.parseInt(line2[0]),Integer.parseInt(line2[1]));
        }
    } BufferedReader br = new BufferedReader(new InputStreamReader(System.in)); br new BufferedReader(new InputStreamReader(System.in)) while(true) {
            String line = br.readLine();
            String[] line2 = line.split(" ");
            if(Integer.parseInt(line2[0]) == 0)
                if(Integer.parseInt(line2[1]) == 0)
                    break;
            print(Integer.parseInt(line2[0]),Integer.parseInt(line2[1]));
        } true {
            String line = br.readLine();
            String[] line2 = line.split(" ");
            if(Integer.parseInt(line2[0]) == 0)
                if(Integer.parseInt(line2[1]) == 0)
                    break;
            print(Integer.parseInt(line2[0]),Integer.parseInt(line2[1]));
        } String line = br.readLine(); line br.readLine() br.readLine br String[] line2 = line.split(" "); line2 line.split(" ") line.split line " " if(Integer.parseInt(line2[0]) == 0)
                if(Integer.parseInt(line2[1]) == 0)
                    break; Integer.parseInt(line2[0]) == 0 Integer.parseInt(line2[0]) Integer.parseInt Integer line2[0] line2 0 0 if(Integer.parseInt(line2[1]) == 0)
                    break; Integer.parseInt(line2[1]) == 0 Integer.parseInt(line2[1]) Integer.parseInt Integer line2[1] line2 1 0 break; print(Integer.parseInt(line2[0]),Integer.parseInt(line2[1])) print Integer.parseInt(line2[0]) Integer.parseInt Integer line2[0] line2 0 Integer.parseInt(line2[1]) Integer.parseInt Integer line2[1] line2 1 String[] args args static void print(int h,int w) {
        for(int i=0;i < h;i++) {
            for(int j = 0; j < w ; 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();

    } print {
        for(int i=0;i < h;i++) {
            for(int j = 0; j < w ; 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(int i=0;i < h;i++) {
            for(int j = 0; j < w ; 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();
        } int i=0; int i=0; i 0 i < h i h i++ i++ i {
            for(int j = 0; j < w ; 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(int j = 0; j < w ; 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(int j = 0; j < w ; 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("#");
                    }
                }
            } int j = 0; int j = 0; j 0 j < w j w 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 int h h int w w public class Main {
    public static void main(String[] args) throws Exception {
        // Here your code !
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        while(true) {
            String line = br.readLine();
            String[] line2 = line.split(" ");
            if(Integer.parseInt(line2[0]) == 0)
                if(Integer.parseInt(line2[1]) == 0)
                    break;
            print(Integer.parseInt(line2[0]),Integer.parseInt(line2[1]));
        }
    }
    static void print(int h,int w) {
        for(int i=0;i < h;i++) {
            for(int j = 0; j < w ; 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) throws Exception {
        // Here your code !
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        while(true) {
            String line = br.readLine();
            String[] line2 = line.split(" ");
            if(Integer.parseInt(line2[0]) == 0)
                if(Integer.parseInt(line2[1]) == 0)
                    break;
            print(Integer.parseInt(line2[0]),Integer.parseInt(line2[1]));
        }
    }
    static void print(int h,int w) {
        for(int i=0;i < h;i++) {
            for(int j = 0; j < w ; 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.io.BufferedReader;
import java.io.InputStreamReader;

public class Main {
    public static void main(String[] args) throws Exception {
        // Here your code !
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        while(true) {
            String line = br.readLine();
            String[] line2 = line.split(" ");
            if(Integer.parseInt(line2[0]) == 0)
                if(Integer.parseInt(line2[1]) == 0)
                    break;
            print(Integer.parseInt(line2[0]),Integer.parseInt(line2[1]));
        }
    }
    static void print(int h,int w) {
        for(int i=0;i < h;i++) {
            for(int j = 0; j < w ; 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();

    }
}