import java.util.Scanner;
import java.io.*;

public class NQueens {
    public static int boardsize;
    public static final int empty = 0;
    public static final int queen = 1;
    private static int board[][];

    public static Scanner in;
    public static PrintWriter out1;

    public static void main(String args[]) throws IOException{
    	String input = null;
    	BufferedReader reader = null;

		try {
			File file = new File("sample-file.dat");
			reader = new BufferedReader(new FileReader("in.txt"));

			if((input = reader.readLine()) == null) {}

		} catch (IOException e) {
			e.printStackTrace();
		}finally {
		try {
	        reader.close();
	    } catch (IOException e) {
	        e.printStackTrace();
	    }
		}

		//['4' , '1' , '2']
		String[] in = input.split(" ");
		for(String s : in) {
			System.out.println(s);
		}

        //while(s.hasNextInt()) {
            int a = Integer.parseInt(in[0]);
            boardsize = a; //set board size
            int c = Integer.parseInt(in[1]); //row
            int b = Integer.parseInt(in[2]); //col
            board = new int[a][a];
            clearBoard();
            /** setQueen(2,2);
            System.out.println("Testing diag \\ 1,1 " +isUnderAttack(1,1));
            System.out.println("Testing up 2,1 " +isUnderAttack(2,1));
            System.out.println("Testing diag // 3,1 " +isUnderAttack(3,1));
            System.out.println("Testing left 1,2 " +isUnderAttack(1,2));
            System.out.println("Testing right 3,2 " +isUnderAttack(3,2));
            System.out.println("Testing diag // 1,3 " +isUnderAttack(1,3));
            System.out.println("Testing down 2,3 " +isUnderAttack(2,3));
            System.out.println("Testing diag \\ 3,3 " +isUnderAttack(3,3));
            System.out.println("Testing further down 2,4 " +isUnderAttack(2,4));
            System.out.println("Testing further diag \\ 4,4 " +isUnderAttack(4,4));
            System.out.println("Testing further right 4,2 " +isUnderAttack(4,2));
            */
            setQueen(b,c);

            placeQueens(b);
            printQueens();


        }


     //queens1.setQueen(2, 3);
     //queens1.setQueen(1, 2);
     //queens1.displayBoard();
     //System.out.println(queens1.isUnderAttack(1, 2));

    public NQueens() {
        // scan = new Scanner(System.in);
        // int i = scan.nextInt();

        board = new int[boardsize][boardsize];
    }

    public static void clearBoard() {

        int row = board.length;
        int col = board.length;

        for (int y = 0; y < col; y++) {
            for (int x = 0; x < row; x++) {
                board[x][y] = empty;
            }
        }

    }

    public void displayBoard() {

        int row = board.length;
        int col = board.length;

        for (int y = 0; y < row; y++) {
            System.out.println("");
            for (int x = 0; x < col; x++) {
                if (board[y][x] == empty) {
                    System.out.print("0");
                } else {
                    System.out.print("1");
                }
            }
        }
    }

    public static boolean placeQueens(int column) {
        if (column > boardsize) {
            return true; // base case
        } else {
            boolean queenPlaced = false;
            int row = 1; // number of square in column
            while (!queenPlaced && (row <= boardsize)) {
                // if square can be attacked
            	printQueens();
                if (isUnderAttack(row, column)) {
                    ++row; // consider next square in column
                } // end if
                else { // place queen and consider next column
                    setQueen(row, column);
                    queenPlaced = placeQueens(column + 1);
                    // if no queen is possible in next column,
                    if (!queenPlaced) {
                        // backtrack: remove queen placed earlier
                        // and try next square in column
                        removeQueen(row, column);
                        ++row;
                    } // end if
                } // end if
            } // end while
            return queenPlaced;
        } // end if
    } // end placeQueens

    private static void setQueen(int row, int column) {
        board[row - 1][column - 1] = 1;
    }

    private static void removeQueen(int row, int column) {
        board[row - 1][column - 1] = empty;
    }

    private static boolean isUnderAttack(int row, int column) {
    	int r = row - 1;
        int c = column - 1;

        for (int y = 0; y < board.length; y++) {
            if (board[y][c] == 1) {
                return true;
            }
        }

        r = row - 1;
        c = column - 1;
        for (int x = 0; x < board.length; x++) {
            if (board[r][x] == 1) {
                return true;
            }
        }

        r = row - 1;
        c = column - 1;
        while(r < board.length && c < board.length) {
            if (board[r][c] == 1) {
                return true;
            }
            r++;
            c++;
        }

        r = row - 1;
        c = column - 1;
        while(r < board.length && c >= 0) {
            if (board[r][c] == 1) {
                return true;
            }
            r++;
            c--;
        }

        r = row - 1;
        c = column - 1;
        while(r >= 0 && c < board.length) {
            if (board[r][c] == 1) {
                return true;
            }
            r--;
            c++;
        }

        r = row - 1;
        c = column - 1;
        while(r >= 0 && c >= 0) {
            if (board[r][c] == 1) {
                return true;
            }
            r--;
            c--;
        }
        return false;
    }

    public static void printQueens() {
    	String result = "";
        for(int x = 0; x < board.length; x++) {
            for(int y = 0; y < board.length; y++) {
                if (board[x][y]==0 ) // no queen
                {
                    result += ".";
                }
                else //queen
                	result += "Q";
            }
            result += "\n";
        }
        System.out.println(result);
    }
}