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

/**
 * http://judge.u-aizu.ac.jp/onlinejudge/description.jsp?id=ITP1_5_C
 * 
 * @author eitatsuro
 * 
 */
public class Main {
    static final String HASHMARK = "#";
    static final String DOTMARK  = ".";
    
    public static void main(String[] args) {
        try {
            BufferedReader stdReader = new BufferedReader(
                    new InputStreamReader(System.in));
            
            String sStr;
            while ((sStr = stdReader.readLine()) != null) {
                String[] inputs = sStr.split(" ");
                
                int h = Integer.valueOf(inputs[0]);
                int w = Integer.valueOf(inputs[1]);
                
                if (h == 0 && w == 0) {
                    break;
                    // nothing to do.
                }
                
                for (int i = 0; i < h; i++) {
                    for (int j = 0; j < w; j++) {
                        if ( ( j-i ) %2 != 0) {
                            System.out.print(DOTMARK);
                        } else {
                            System.out.print(HASHMARK);
                        }
                    }
                    System.out.println();
                }
                System.out.println();
            }
            stdReader.close();
        } catch (Exception e) {
            System.exit(-1);
        }
    }
} import java.io.BufferedReader; BufferedReader java.io import java.io.InputStreamReader; InputStreamReader java.io public class Main {
    static final String HASHMARK = "#";
    static final String DOTMARK  = ".";
    
    public static void main(String[] args) {
        try {
            BufferedReader stdReader = new BufferedReader(
                    new InputStreamReader(System.in));
            
            String sStr;
            while ((sStr = stdReader.readLine()) != null) {
                String[] inputs = sStr.split(" ");
                
                int h = Integer.valueOf(inputs[0]);
                int w = Integer.valueOf(inputs[1]);
                
                if (h == 0 && w == 0) {
                    break;
                    // nothing to do.
                }
                
                for (int i = 0; i < h; i++) {
                    for (int j = 0; j < w; j++) {
                        if ( ( j-i ) %2 != 0) {
                            System.out.print(DOTMARK);
                        } else {
                            System.out.print(HASHMARK);
                        }
                    }
                    System.out.println();
                }
                System.out.println();
            }
            stdReader.close();
        } catch (Exception e) {
            System.exit(-1);
        }
    }
} Main static final String HASHMARK = "#"; HASHMARK "#" static final String DOTMARK  = "."; DOTMARK "." public static void main(String[] args) {
        try {
            BufferedReader stdReader = new BufferedReader(
                    new InputStreamReader(System.in));
            
            String sStr;
            while ((sStr = stdReader.readLine()) != null) {
                String[] inputs = sStr.split(" ");
                
                int h = Integer.valueOf(inputs[0]);
                int w = Integer.valueOf(inputs[1]);
                
                if (h == 0 && w == 0) {
                    break;
                    // nothing to do.
                }
                
                for (int i = 0; i < h; i++) {
                    for (int j = 0; j < w; j++) {
                        if ( ( j-i ) %2 != 0) {
                            System.out.print(DOTMARK);
                        } else {
                            System.out.print(HASHMARK);
                        }
                    }
                    System.out.println();
                }
                System.out.println();
            }
            stdReader.close();
        } catch (Exception e) {
            System.exit(-1);
        }
    } main {
        try {
            BufferedReader stdReader = new BufferedReader(
                    new InputStreamReader(System.in));
            
            String sStr;
            while ((sStr = stdReader.readLine()) != null) {
                String[] inputs = sStr.split(" ");
                
                int h = Integer.valueOf(inputs[0]);
                int w = Integer.valueOf(inputs[1]);
                
                if (h == 0 && w == 0) {
                    break;
                    // nothing to do.
                }
                
                for (int i = 0; i < h; i++) {
                    for (int j = 0; j < w; j++) {
                        if ( ( j-i ) %2 != 0) {
                            System.out.print(DOTMARK);
                        } else {
                            System.out.print(HASHMARK);
                        }
                    }
                    System.out.println();
                }
                System.out.println();
            }
            stdReader.close();
        } catch (Exception e) {
            System.exit(-1);
        }
    } try {
            BufferedReader stdReader = new BufferedReader(
                    new InputStreamReader(System.in));
            
            String sStr;
            while ((sStr = stdReader.readLine()) != null) {
                String[] inputs = sStr.split(" ");
                
                int h = Integer.valueOf(inputs[0]);
                int w = Integer.valueOf(inputs[1]);
                
                if (h == 0 && w == 0) {
                    break;
                    // nothing to do.
                }
                
                for (int i = 0; i < h; i++) {
                    for (int j = 0; j < w; j++) {
                        if ( ( j-i ) %2 != 0) {
                            System.out.print(DOTMARK);
                        } else {
                            System.out.print(HASHMARK);
                        }
                    }
                    System.out.println();
                }
                System.out.println();
            }
            stdReader.close();
        } catch (Exception e) {
            System.exit(-1);
        } catch (Exception e) {
            System.exit(-1);
        } Exception e {
            System.exit(-1);
        } System.exit(-1) System.exit System -1 1 {
            BufferedReader stdReader = new BufferedReader(
                    new InputStreamReader(System.in));
            
            String sStr;
            while ((sStr = stdReader.readLine()) != null) {
                String[] inputs = sStr.split(" ");
                
                int h = Integer.valueOf(inputs[0]);
                int w = Integer.valueOf(inputs[1]);
                
                if (h == 0 && w == 0) {
                    break;
                    // nothing to do.
                }
                
                for (int i = 0; i < h; i++) {
                    for (int j = 0; j < w; j++) {
                        if ( ( j-i ) %2 != 0) {
                            System.out.print(DOTMARK);
                        } else {
                            System.out.print(HASHMARK);
                        }
                    }
                    System.out.println();
                }
                System.out.println();
            }
            stdReader.close();
        } BufferedReader stdReader = new BufferedReader(
                    new InputStreamReader(System.in)); stdReader new BufferedReader(
                    new InputStreamReader(System.in)) String sStr; sStr while ((sStr = stdReader.readLine()) != null) {
                String[] inputs = sStr.split(" ");
                
                int h = Integer.valueOf(inputs[0]);
                int w = Integer.valueOf(inputs[1]);
                
                if (h == 0 && w == 0) {
                    break;
                    // nothing to do.
                }
                
                for (int i = 0; i < h; i++) {
                    for (int j = 0; j < w; j++) {
                        if ( ( j-i ) %2 != 0) {
                            System.out.print(DOTMARK);
                        } else {
                            System.out.print(HASHMARK);
                        }
                    }
                    System.out.println();
                }
                System.out.println();
            } (sStr = stdReader.readLine()) != null (sStr = stdReader.readLine()) sStr stdReader.readLine() stdReader.readLine stdReader null {
                String[] inputs = sStr.split(" ");
                
                int h = Integer.valueOf(inputs[0]);
                int w = Integer.valueOf(inputs[1]);
                
                if (h == 0 && w == 0) {
                    break;
                    // nothing to do.
                }
                
                for (int i = 0; i < h; i++) {
                    for (int j = 0; j < w; j++) {
                        if ( ( j-i ) %2 != 0) {
                            System.out.print(DOTMARK);
                        } else {
                            System.out.print(HASHMARK);
                        }
                    }
                    System.out.println();
                }
                System.out.println();
            } String[] inputs = sStr.split(" "); inputs sStr.split(" ") sStr.split sStr " " int h = Integer.valueOf(inputs[0]); h Integer.valueOf(inputs[0]) Integer.valueOf Integer inputs[0] inputs 0 int w = Integer.valueOf(inputs[1]); w Integer.valueOf(inputs[1]) Integer.valueOf Integer inputs[1] inputs 1 if (h == 0 && w == 0) {
                    break;
                    // nothing to do.
                } h == 0 && w == 0 h == 0 h 0 w == 0 w 0 {
                    break;
                    // nothing to do.
                } break; for (int i = 0; i < h; i++) {
                    for (int j = 0; j < w; j++) {
                        if ( ( j-i ) %2 != 0) {
                            System.out.print(DOTMARK);
                        } else {
                            System.out.print(HASHMARK);
                        }
                    }
                    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 ( ( j-i ) %2 != 0) {
                            System.out.print(DOTMARK);
                        } else {
                            System.out.print(HASHMARK);
                        }
                    }
                    System.out.println();
                } {
                    for (int j = 0; j < w; j++) {
                        if ( ( j-i ) %2 != 0) {
                            System.out.print(DOTMARK);
                        } else {
                            System.out.print(HASHMARK);
                        }
                    }
                    System.out.println();
                } for (int j = 0; j < w; j++) {
                        if ( ( j-i ) %2 != 0) {
                            System.out.print(DOTMARK);
                        } else {
                            System.out.print(HASHMARK);
                        }
                    } int j = 0; int j = 0; j 0 j < w j w j++ j++ j {
                        if ( ( j-i ) %2 != 0) {
                            System.out.print(DOTMARK);
                        } else {
                            System.out.print(HASHMARK);
                        }
                    } {
                        if ( ( j-i ) %2 != 0) {
                            System.out.print(DOTMARK);
                        } else {
                            System.out.print(HASHMARK);
                        }
                    } if ( ( j-i ) %2 != 0) {
                            System.out.print(DOTMARK);
                        } else {
                            System.out.print(HASHMARK);
                        } ( j-i ) %2 != 0 ( j-i ) %2 ( j-i ) j i 2 0 {
                            System.out.print(DOTMARK);
                        } System.out.print(DOTMARK) System.out.print System.out System System.out DOTMARK {
                            System.out.print(HASHMARK);
                        } System.out.print(HASHMARK) System.out.print System.out System System.out HASHMARK System.out.println() System.out.println System.out System System.out System.out.println() System.out.println System.out System System.out stdReader.close() stdReader.close stdReader String[] args args public class Main {
    static final String HASHMARK = "#";
    static final String DOTMARK  = ".";
    
    public static void main(String[] args) {
        try {
            BufferedReader stdReader = new BufferedReader(
                    new InputStreamReader(System.in));
            
            String sStr;
            while ((sStr = stdReader.readLine()) != null) {
                String[] inputs = sStr.split(" ");
                
                int h = Integer.valueOf(inputs[0]);
                int w = Integer.valueOf(inputs[1]);
                
                if (h == 0 && w == 0) {
                    break;
                    // nothing to do.
                }
                
                for (int i = 0; i < h; i++) {
                    for (int j = 0; j < w; j++) {
                        if ( ( j-i ) %2 != 0) {
                            System.out.print(DOTMARK);
                        } else {
                            System.out.print(HASHMARK);
                        }
                    }
                    System.out.println();
                }
                System.out.println();
            }
            stdReader.close();
        } catch (Exception e) {
            System.exit(-1);
        }
    }
} public class Main {
    static final String HASHMARK = "#";
    static final String DOTMARK  = ".";
    
    public static void main(String[] args) {
        try {
            BufferedReader stdReader = new BufferedReader(
                    new InputStreamReader(System.in));
            
            String sStr;
            while ((sStr = stdReader.readLine()) != null) {
                String[] inputs = sStr.split(" ");
                
                int h = Integer.valueOf(inputs[0]);
                int w = Integer.valueOf(inputs[1]);
                
                if (h == 0 && w == 0) {
                    break;
                    // nothing to do.
                }
                
                for (int i = 0; i < h; i++) {
                    for (int j = 0; j < w; j++) {
                        if ( ( j-i ) %2 != 0) {
                            System.out.print(DOTMARK);
                        } else {
                            System.out.print(HASHMARK);
                        }
                    }
                    System.out.println();
                }
                System.out.println();
            }
            stdReader.close();
        } catch (Exception e) {
            System.exit(-1);
        }
    }
} Main
import java.io.BufferedReader;
import java.io.InputStreamReader;

/**
 * http://judge.u-aizu.ac.jp/onlinejudge/description.jsp?id=ITP1_5_C
 * 
 * @author eitatsuro
 * 
 */
public class Main {
    static final String HASHMARK = "#";
    static final String DOTMARK  = ".";
    
    public static void main(String[] args) {
        try {
            BufferedReader stdReader = new BufferedReader(
                    new InputStreamReader(System.in));
            
            String sStr;
            while ((sStr = stdReader.readLine()) != null) {
                String[] inputs = sStr.split(" ");
                
                int h = Integer.valueOf(inputs[0]);
                int w = Integer.valueOf(inputs[1]);
                
                if (h == 0 && w == 0) {
                    break;
                    // nothing to do.
                }
                
                for (int i = 0; i < h; i++) {
                    for (int j = 0; j < w; j++) {
                        if ( ( j-i ) %2 != 0) {
                            System.out.print(DOTMARK);
                        } else {
                            System.out.print(HASHMARK);
                        }
                    }
                    System.out.println();
                }
                System.out.println();
            }
            stdReader.close();
        } catch (Exception e) {
            System.exit(-1);
        }
    }
}