import java.util.Scanner;

public class Main {
    public static void main(String arg[]) {
        Scanner sc = new Scanner(System.in);
        
        
        for(int x = 1; x < 10000; x++) {
            
            int H = sc.nextInt();
            int W = sc.nextInt();
            
            if(printJudge(H, W)) {
            
                for(int i = 1; i < H + 1; i++) {
                    if((double)i % 2 != 0) {
                        printLine1(W);
                    }else {
                        printLine2(W);
                    }
                }
            }else {
                break;
            }
            
            System.out.print("\n");
            
        }        
    }

    public static void printLine1(int W) {
        for(int i = 1; i < W + 1; i ++) {
            if((double)i % 2 != 0) {
                System.out.print("#");
            }else {
                System.out.print(".");
            }
        }
        System.out.print("\n");
    }
    
    public static void printLine2(int W) {
        for(int i = 1; i < W + 1; i ++) {
            if((double)i % 2 != 0) {
                System.out.print(".");
            }else {
                System.out.print("#");
            }
        }
        System.out.print("\n");
    }
    
    public static boolean printJudge(int H, int W) {
        if(H < 1 || W < 1 || H > 300 || W > 300) {
            return false;
	}else if(H == 0 && W == 0) {
            return false;
            
        }else return true;
    }
} import java.util.Scanner; Scanner java.util public class Main {
    public static void main(String arg[]) {
        Scanner sc = new Scanner(System.in);
        
        
        for(int x = 1; x < 10000; x++) {
            
            int H = sc.nextInt();
            int W = sc.nextInt();
            
            if(printJudge(H, W)) {
            
                for(int i = 1; i < H + 1; i++) {
                    if((double)i % 2 != 0) {
                        printLine1(W);
                    }else {
                        printLine2(W);
                    }
                }
            }else {
                break;
            }
            
            System.out.print("\n");
            
        }        
    }

    public static void printLine1(int W) {
        for(int i = 1; i < W + 1; i ++) {
            if((double)i % 2 != 0) {
                System.out.print("#");
            }else {
                System.out.print(".");
            }
        }
        System.out.print("\n");
    }
    
    public static void printLine2(int W) {
        for(int i = 1; i < W + 1; i ++) {
            if((double)i % 2 != 0) {
                System.out.print(".");
            }else {
                System.out.print("#");
            }
        }
        System.out.print("\n");
    }
    
    public static boolean printJudge(int H, int W) {
        if(H < 1 || W < 1 || H > 300 || W > 300) {
            return false;
	}else if(H == 0 && W == 0) {
            return false;
            
        }else return true;
    }
} Main public static void main(String arg[]) {
        Scanner sc = new Scanner(System.in);
        
        
        for(int x = 1; x < 10000; x++) {
            
            int H = sc.nextInt();
            int W = sc.nextInt();
            
            if(printJudge(H, W)) {
            
                for(int i = 1; i < H + 1; i++) {
                    if((double)i % 2 != 0) {
                        printLine1(W);
                    }else {
                        printLine2(W);
                    }
                }
            }else {
                break;
            }
            
            System.out.print("\n");
            
        }        
    } main {
        Scanner sc = new Scanner(System.in);
        
        
        for(int x = 1; x < 10000; x++) {
            
            int H = sc.nextInt();
            int W = sc.nextInt();
            
            if(printJudge(H, W)) {
            
                for(int i = 1; i < H + 1; i++) {
                    if((double)i % 2 != 0) {
                        printLine1(W);
                    }else {
                        printLine2(W);
                    }
                }
            }else {
                break;
            }
            
            System.out.print("\n");
            
        }        
    } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) for(int x = 1; x < 10000; x++) {
            
            int H = sc.nextInt();
            int W = sc.nextInt();
            
            if(printJudge(H, W)) {
            
                for(int i = 1; i < H + 1; i++) {
                    if((double)i % 2 != 0) {
                        printLine1(W);
                    }else {
                        printLine2(W);
                    }
                }
            }else {
                break;
            }
            
            System.out.print("\n");
            
        } int x = 1; int x = 1; x 1 x < 10000 x 10000 x++ x++ x {
            
            int H = sc.nextInt();
            int W = sc.nextInt();
            
            if(printJudge(H, W)) {
            
                for(int i = 1; i < H + 1; i++) {
                    if((double)i % 2 != 0) {
                        printLine1(W);
                    }else {
                        printLine2(W);
                    }
                }
            }else {
                break;
            }
            
            System.out.print("\n");
            
        } {
            
            int H = sc.nextInt();
            int W = sc.nextInt();
            
            if(printJudge(H, W)) {
            
                for(int i = 1; i < H + 1; i++) {
                    if((double)i % 2 != 0) {
                        printLine1(W);
                    }else {
                        printLine2(W);
                    }
                }
            }else {
                break;
            }
            
            System.out.print("\n");
            
        } int H = sc.nextInt(); H sc.nextInt() sc.nextInt sc int W = sc.nextInt(); W sc.nextInt() sc.nextInt sc if(printJudge(H, W)) {
            
                for(int i = 1; i < H + 1; i++) {
                    if((double)i % 2 != 0) {
                        printLine1(W);
                    }else {
                        printLine2(W);
                    }
                }
            }else {
                break;
            } printJudge(H, W) printJudge H W {
            
                for(int i = 1; i < H + 1; i++) {
                    if((double)i % 2 != 0) {
                        printLine1(W);
                    }else {
                        printLine2(W);
                    }
                }
            } for(int i = 1; i < H + 1; i++) {
                    if((double)i % 2 != 0) {
                        printLine1(W);
                    }else {
                        printLine2(W);
                    }
                } int i = 1; int i = 1; i 1 i < H + 1 i H + 1 H 1 i++ i++ i {
                    if((double)i % 2 != 0) {
                        printLine1(W);
                    }else {
                        printLine2(W);
                    }
                } {
                    if((double)i % 2 != 0) {
                        printLine1(W);
                    }else {
                        printLine2(W);
                    }
                } if((double)i % 2 != 0) {
                        printLine1(W);
                    }else {
                        printLine2(W);
                    } (double)i % 2 != 0 (double)i % 2 (double)i 2 0 {
                        printLine1(W);
                    } printLine1(W) printLine1 W {
                        printLine2(W);
                    } printLine2(W) printLine2 W {
                break;
            } break; System.out.print("\n") System.out.print System.out System System.out "\n" String arg[] arg public static void printLine1(int W) {
        for(int i = 1; i < W + 1; i ++) {
            if((double)i % 2 != 0) {
                System.out.print("#");
            }else {
                System.out.print(".");
            }
        }
        System.out.print("\n");
    } printLine1 {
        for(int i = 1; i < W + 1; i ++) {
            if((double)i % 2 != 0) {
                System.out.print("#");
            }else {
                System.out.print(".");
            }
        }
        System.out.print("\n");
    } for(int i = 1; i < W + 1; i ++) {
            if((double)i % 2 != 0) {
                System.out.print("#");
            }else {
                System.out.print(".");
            }
        } int i = 1; int i = 1; i 1 i < W + 1 i W + 1 W 1 i ++ i ++ i {
            if((double)i % 2 != 0) {
                System.out.print("#");
            }else {
                System.out.print(".");
            }
        } {
            if((double)i % 2 != 0) {
                System.out.print("#");
            }else {
                System.out.print(".");
            }
        } if((double)i % 2 != 0) {
                System.out.print("#");
            }else {
                System.out.print(".");
            } (double)i % 2 != 0 (double)i % 2 (double)i 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.print("\n") System.out.print System.out System System.out "\n" int W W public static void printLine2(int W) {
        for(int i = 1; i < W + 1; i ++) {
            if((double)i % 2 != 0) {
                System.out.print(".");
            }else {
                System.out.print("#");
            }
        }
        System.out.print("\n");
    } printLine2 {
        for(int i = 1; i < W + 1; i ++) {
            if((double)i % 2 != 0) {
                System.out.print(".");
            }else {
                System.out.print("#");
            }
        }
        System.out.print("\n");
    } for(int i = 1; i < W + 1; i ++) {
            if((double)i % 2 != 0) {
                System.out.print(".");
            }else {
                System.out.print("#");
            }
        } int i = 1; int i = 1; i 1 i < W + 1 i W + 1 W 1 i ++ i ++ i {
            if((double)i % 2 != 0) {
                System.out.print(".");
            }else {
                System.out.print("#");
            }
        } {
            if((double)i % 2 != 0) {
                System.out.print(".");
            }else {
                System.out.print("#");
            }
        } if((double)i % 2 != 0) {
                System.out.print(".");
            }else {
                System.out.print("#");
            } (double)i % 2 != 0 (double)i % 2 (double)i 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.print("\n") System.out.print System.out System System.out "\n" int W W public static boolean printJudge(int H, int W) {
        if(H < 1 || W < 1 || H > 300 || W > 300) {
            return false;
	}else if(H == 0 && W == 0) {
            return false;
            
        }else return true;
    } printJudge {
        if(H < 1 || W < 1 || H > 300 || W > 300) {
            return false;
	}else if(H == 0 && W == 0) {
            return false;
            
        }else return true;
    } if(H < 1 || W < 1 || H > 300 || W > 300) {
            return false;
	}else if(H == 0 && W == 0) {
            return false;
            
        }else return true; H < 1 || W < 1 || H > 300 || W > 300 H > 300 H < 1 || W < 1 || H > 300 || W > 300 H < 1 H 1 W < 1 W 1 H > 300 H 300 W > 300 W 300 {
            return false;
	} return false; false if(H == 0 && W == 0) {
            return false;
            
        }else return true; H == 0 && W == 0 H == 0 H 0 W == 0 W 0 {
            return false;
            
        } return false; false return true; true int H H int W W public class Main {
    public static void main(String arg[]) {
        Scanner sc = new Scanner(System.in);
        
        
        for(int x = 1; x < 10000; x++) {
            
            int H = sc.nextInt();
            int W = sc.nextInt();
            
            if(printJudge(H, W)) {
            
                for(int i = 1; i < H + 1; i++) {
                    if((double)i % 2 != 0) {
                        printLine1(W);
                    }else {
                        printLine2(W);
                    }
                }
            }else {
                break;
            }
            
            System.out.print("\n");
            
        }        
    }

    public static void printLine1(int W) {
        for(int i = 1; i < W + 1; i ++) {
            if((double)i % 2 != 0) {
                System.out.print("#");
            }else {
                System.out.print(".");
            }
        }
        System.out.print("\n");
    }
    
    public static void printLine2(int W) {
        for(int i = 1; i < W + 1; i ++) {
            if((double)i % 2 != 0) {
                System.out.print(".");
            }else {
                System.out.print("#");
            }
        }
        System.out.print("\n");
    }
    
    public static boolean printJudge(int H, int W) {
        if(H < 1 || W < 1 || H > 300 || W > 300) {
            return false;
	}else if(H == 0 && W == 0) {
            return false;
            
        }else return true;
    }
} public class Main {
    public static void main(String arg[]) {
        Scanner sc = new Scanner(System.in);
        
        
        for(int x = 1; x < 10000; x++) {
            
            int H = sc.nextInt();
            int W = sc.nextInt();
            
            if(printJudge(H, W)) {
            
                for(int i = 1; i < H + 1; i++) {
                    if((double)i % 2 != 0) {
                        printLine1(W);
                    }else {
                        printLine2(W);
                    }
                }
            }else {
                break;
            }
            
            System.out.print("\n");
            
        }        
    }

    public static void printLine1(int W) {
        for(int i = 1; i < W + 1; i ++) {
            if((double)i % 2 != 0) {
                System.out.print("#");
            }else {
                System.out.print(".");
            }
        }
        System.out.print("\n");
    }
    
    public static void printLine2(int W) {
        for(int i = 1; i < W + 1; i ++) {
            if((double)i % 2 != 0) {
                System.out.print(".");
            }else {
                System.out.print("#");
            }
        }
        System.out.print("\n");
    }
    
    public static boolean printJudge(int H, int W) {
        if(H < 1 || W < 1 || H > 300 || W > 300) {
            return false;
	}else if(H == 0 && W == 0) {
            return false;
            
        }else return true;
    }
} Main
import java.util.Scanner;

public class Main {
    public static void main(String arg[]) {
        Scanner sc = new Scanner(System.in);
        
        
        for(int x = 1; x < 10000; x++) {
            
            int H = sc.nextInt();
            int W = sc.nextInt();
            
            if(printJudge(H, W)) {
            
                for(int i = 1; i < H + 1; i++) {
                    if((double)i % 2 != 0) {
                        printLine1(W);
                    }else {
                        printLine2(W);
                    }
                }
            }else {
                break;
            }
            
            System.out.print("\n");
            
        }        
    }

    public static void printLine1(int W) {
        for(int i = 1; i < W + 1; i ++) {
            if((double)i % 2 != 0) {
                System.out.print("#");
            }else {
                System.out.print(".");
            }
        }
        System.out.print("\n");
    }
    
    public static void printLine2(int W) {
        for(int i = 1; i < W + 1; i ++) {
            if((double)i % 2 != 0) {
                System.out.print(".");
            }else {
                System.out.print("#");
            }
        }
        System.out.print("\n");
    }
    
    public static boolean printJudge(int H, int W) {
        if(H < 1 || W < 1 || H > 300 || W > 300) {
            return false;
	}else if(H == 0 && W == 0) {
            return false;
            
        }else return true;
    }
}