import java.util.ArrayList;
import java.util.Scanner;

public class Main {
		public static int exception(int h,int w){
			int result = 0;
			if(1 <= h && h <= 300 && 1 <= w && w <= 300){ //??????????????????(??\????¶???????)
				result = 2;
			}
			else if(h == 0 && w == 0){
				result = 1; //0,0??\?????§??\???????????????
			}
			else{
				System.out.println("1~300????????§.???????????????.");
				result = 0;
			}
			return result;
		}
		public static void main(String[] args) {
			/**
			 * ?????°?????£?¨?
			 */
			int a = 0;
			int t = 0, inc = 0;
			int h = 0,w = 0; //height:h width:w
			int x = 0;
			/**
			 * ???????????£?¨?
			 */
			ArrayList<String> st = new ArrayList<String>();
			ArrayList<Integer> parse = new ArrayList<Integer>();
			/**
			 * ????¨???????????????\???
			 */
			Scanner scan = new Scanner(System.in);
			while(a == 0){
			for (t = 0; t < 2; t++){ //??´??°2???????????????
			st.add(scan.next());
			}
			h = Integer.parseInt(st.get(inc));
			w = Integer.parseInt(st.get(inc+1));
			parse.add(h);
			parse.add(w);
			if(exception(h,w) == 1){ //h=w=0?????¨??????????????????????????????
				break;
			}
			else if(exception(h,w) == 0){ //??????????????????????????????.
				System.exit(0);
			}
			inc = inc + 2; //???????????§?????°
			}
			/**
			 * ??????
			 */
			for(int n= 1; n < ((parse.size())/2) ; ++n){ //???????????°??????
			 for(int i = 1; i < parse.get(2*(n-1))+1; ++i){ //hight
				for(int j = 1; j < parse.get(2*n-1)+1; ++j){ //width
				if((i + j) % 2 == 0){
					System.out.print("#");
				}
				else if((i + j) % 2 != 0 ){
					System.out.print(".");
				}
				}
				System.out.println("");
			 }
			 System.out.println("");
			}
		}
	} import java.util.ArrayList; ArrayList java.util import java.util.Scanner; Scanner java.util public class Main {
		public static int exception(int h,int w){
			int result = 0;
			if(1 <= h && h <= 300 && 1 <= w && w <= 300){ //??????????????????(??\????¶???????)
				result = 2;
			}
			else if(h == 0 && w == 0){
				result = 1; //0,0??\?????§??\???????????????
			}
			else{
				System.out.println("1~300????????§.???????????????.");
				result = 0;
			}
			return result;
		}
		public static void main(String[] args) {
			/**
			 * ?????°?????£?¨?
			 */
			int a = 0;
			int t = 0, inc = 0;
			int h = 0,w = 0; //height:h width:w
			int x = 0;
			/**
			 * ???????????£?¨?
			 */
			ArrayList<String> st = new ArrayList<String>();
			ArrayList<Integer> parse = new ArrayList<Integer>();
			/**
			 * ????¨???????????????\???
			 */
			Scanner scan = new Scanner(System.in);
			while(a == 0){
			for (t = 0; t < 2; t++){ //??´??°2???????????????
			st.add(scan.next());
			}
			h = Integer.parseInt(st.get(inc));
			w = Integer.parseInt(st.get(inc+1));
			parse.add(h);
			parse.add(w);
			if(exception(h,w) == 1){ //h=w=0?????¨??????????????????????????????
				break;
			}
			else if(exception(h,w) == 0){ //??????????????????????????????.
				System.exit(0);
			}
			inc = inc + 2; //???????????§?????°
			}
			/**
			 * ??????
			 */
			for(int n= 1; n < ((parse.size())/2) ; ++n){ //???????????°??????
			 for(int i = 1; i < parse.get(2*(n-1))+1; ++i){ //hight
				for(int j = 1; j < parse.get(2*n-1)+1; ++j){ //width
				if((i + j) % 2 == 0){
					System.out.print("#");
				}
				else if((i + j) % 2 != 0 ){
					System.out.print(".");
				}
				}
				System.out.println("");
			 }
			 System.out.println("");
			}
		}
	} Main public static int exception(int h,int w){
			int result = 0;
			if(1 <= h && h <= 300 && 1 <= w && w <= 300){ //??????????????????(??\????¶???????)
				result = 2;
			}
			else if(h == 0 && w == 0){
				result = 1; //0,0??\?????§??\???????????????
			}
			else{
				System.out.println("1~300????????§.???????????????.");
				result = 0;
			}
			return result;
		} exception {
			int result = 0;
			if(1 <= h && h <= 300 && 1 <= w && w <= 300){ //??????????????????(??\????¶???????)
				result = 2;
			}
			else if(h == 0 && w == 0){
				result = 1; //0,0??\?????§??\???????????????
			}
			else{
				System.out.println("1~300????????§.???????????????.");
				result = 0;
			}
			return result;
		} int result = 0; result 0 if(1 <= h && h <= 300 && 1 <= w && w <= 300){ //??????????????????(??\????¶???????)
				result = 2;
			}
			else if(h == 0 && w == 0){
				result = 1; //0,0??\?????§??\???????????????
			}
			else{
				System.out.println("1~300????????§.???????????????.");
				result = 0;
			} 1 <= h && h <= 300 && 1 <= w && w <= 300 1 <= w 1 <= h && h <= 300 && 1 <= w && w <= 300 1 <= h 1 h h <= 300 h 300 1 <= w 1 w w <= 300 w 300 { //??????????????????(??\????¶???????)
				result = 2;
			} result = 2 result 2 if(h == 0 && w == 0){
				result = 1; //0,0??\?????§??\???????????????
			}
			else{
				System.out.println("1~300????????§.???????????????.");
				result = 0;
			} h == 0 && w == 0 h == 0 h 0 w == 0 w 0 {
				result = 1; //0,0??\?????§??\???????????????
			} result = 1 result 1 {
				System.out.println("1~300????????§.???????????????.");
				result = 0;
			} System.out.println("1~300????????§.???????????????.") System.out.println System.out System System.out "1~300????????§.???????????????." result = 0 result 0 return result; result int h h int w w public static void main(String[] args) {
			/**
			 * ?????°?????£?¨?
			 */
			int a = 0;
			int t = 0, inc = 0;
			int h = 0,w = 0; //height:h width:w
			int x = 0;
			/**
			 * ???????????£?¨?
			 */
			ArrayList<String> st = new ArrayList<String>();
			ArrayList<Integer> parse = new ArrayList<Integer>();
			/**
			 * ????¨???????????????\???
			 */
			Scanner scan = new Scanner(System.in);
			while(a == 0){
			for (t = 0; t < 2; t++){ //??´??°2???????????????
			st.add(scan.next());
			}
			h = Integer.parseInt(st.get(inc));
			w = Integer.parseInt(st.get(inc+1));
			parse.add(h);
			parse.add(w);
			if(exception(h,w) == 1){ //h=w=0?????¨??????????????????????????????
				break;
			}
			else if(exception(h,w) == 0){ //??????????????????????????????.
				System.exit(0);
			}
			inc = inc + 2; //???????????§?????°
			}
			/**
			 * ??????
			 */
			for(int n= 1; n < ((parse.size())/2) ; ++n){ //???????????°??????
			 for(int i = 1; i < parse.get(2*(n-1))+1; ++i){ //hight
				for(int j = 1; j < parse.get(2*n-1)+1; ++j){ //width
				if((i + j) % 2 == 0){
					System.out.print("#");
				}
				else if((i + j) % 2 != 0 ){
					System.out.print(".");
				}
				}
				System.out.println("");
			 }
			 System.out.println("");
			}
		} main {
			/**
			 * ?????°?????£?¨?
			 */
			int a = 0;
			int t = 0, inc = 0;
			int h = 0,w = 0; //height:h width:w
			int x = 0;
			/**
			 * ???????????£?¨?
			 */
			ArrayList<String> st = new ArrayList<String>();
			ArrayList<Integer> parse = new ArrayList<Integer>();
			/**
			 * ????¨???????????????\???
			 */
			Scanner scan = new Scanner(System.in);
			while(a == 0){
			for (t = 0; t < 2; t++){ //??´??°2???????????????
			st.add(scan.next());
			}
			h = Integer.parseInt(st.get(inc));
			w = Integer.parseInt(st.get(inc+1));
			parse.add(h);
			parse.add(w);
			if(exception(h,w) == 1){ //h=w=0?????¨??????????????????????????????
				break;
			}
			else if(exception(h,w) == 0){ //??????????????????????????????.
				System.exit(0);
			}
			inc = inc + 2; //???????????§?????°
			}
			/**
			 * ??????
			 */
			for(int n= 1; n < ((parse.size())/2) ; ++n){ //???????????°??????
			 for(int i = 1; i < parse.get(2*(n-1))+1; ++i){ //hight
				for(int j = 1; j < parse.get(2*n-1)+1; ++j){ //width
				if((i + j) % 2 == 0){
					System.out.print("#");
				}
				else if((i + j) % 2 != 0 ){
					System.out.print(".");
				}
				}
				System.out.println("");
			 }
			 System.out.println("");
			}
		} int a = 0; a 0 int t = 0 t 0 inc = 0; inc 0 int h = 0 h 0 w = 0; w 0 int x = 0; x 0 ArrayList<String> st = new ArrayList<String>(); st new ArrayList<String>() ArrayList<Integer> parse = new ArrayList<Integer>(); parse new ArrayList<Integer>() Scanner scan = new Scanner(System.in); scan new Scanner(System.in) while(a == 0){
			for (t = 0; t < 2; t++){ //??´??°2???????????????
			st.add(scan.next());
			}
			h = Integer.parseInt(st.get(inc));
			w = Integer.parseInt(st.get(inc+1));
			parse.add(h);
			parse.add(w);
			if(exception(h,w) == 1){ //h=w=0?????¨??????????????????????????????
				break;
			}
			else if(exception(h,w) == 0){ //??????????????????????????????.
				System.exit(0);
			}
			inc = inc + 2; //???????????§?????°
			} a == 0 a 0 {
			for (t = 0; t < 2; t++){ //??´??°2???????????????
			st.add(scan.next());
			}
			h = Integer.parseInt(st.get(inc));
			w = Integer.parseInt(st.get(inc+1));
			parse.add(h);
			parse.add(w);
			if(exception(h,w) == 1){ //h=w=0?????¨??????????????????????????????
				break;
			}
			else if(exception(h,w) == 0){ //??????????????????????????????.
				System.exit(0);
			}
			inc = inc + 2; //???????????§?????°
			} for (t = 0; t < 2; t++){ //??´??°2???????????????
			st.add(scan.next());
			} t = 0; t = 0 t 0 t < 2 t 2 t++ t++ t { //??´??°2???????????????
			st.add(scan.next());
			} { //??´??°2???????????????
			st.add(scan.next());
			} st.add(scan.next()) st.add st scan.next() scan.next scan h = Integer.parseInt(st.get(inc)) h Integer.parseInt(st.get(inc)) Integer.parseInt Integer st.get(inc) st.get st inc w = Integer.parseInt(st.get(inc+1)) w Integer.parseInt(st.get(inc+1)) Integer.parseInt Integer st.get(inc+1) st.get st inc+1 inc 1 parse.add(h) parse.add parse h parse.add(w) parse.add parse w if(exception(h,w) == 1){ //h=w=0?????¨??????????????????????????????
				break;
			}
			else if(exception(h,w) == 0){ //??????????????????????????????.
				System.exit(0);
			} exception(h,w) == 1 exception(h,w) exception h w 1 { //h=w=0?????¨??????????????????????????????
				break;
			} break; if(exception(h,w) == 0){ //??????????????????????????????.
				System.exit(0);
			} exception(h,w) == 0 exception(h,w) exception h w 0 { //??????????????????????????????.
				System.exit(0);
			} System.exit(0) System.exit System 0 inc = inc + 2 inc inc + 2 inc 2 for(int n= 1; n < ((parse.size())/2) ; ++n){ //???????????°??????
			 for(int i = 1; i < parse.get(2*(n-1))+1; ++i){ //hight
				for(int j = 1; j < parse.get(2*n-1)+1; ++j){ //width
				if((i + j) % 2 == 0){
					System.out.print("#");
				}
				else if((i + j) % 2 != 0 ){
					System.out.print(".");
				}
				}
				System.out.println("");
			 }
			 System.out.println("");
			} int n= 1; int n= 1; n 1 n < ((parse.size())/2) n ((parse.size())/2) (parse.size()) parse.size parse 2 ++n ++n n { //???????????°??????
			 for(int i = 1; i < parse.get(2*(n-1))+1; ++i){ //hight
				for(int j = 1; j < parse.get(2*n-1)+1; ++j){ //width
				if((i + j) % 2 == 0){
					System.out.print("#");
				}
				else if((i + j) % 2 != 0 ){
					System.out.print(".");
				}
				}
				System.out.println("");
			 }
			 System.out.println("");
			} { //???????????°??????
			 for(int i = 1; i < parse.get(2*(n-1))+1; ++i){ //hight
				for(int j = 1; j < parse.get(2*n-1)+1; ++j){ //width
				if((i + j) % 2 == 0){
					System.out.print("#");
				}
				else if((i + j) % 2 != 0 ){
					System.out.print(".");
				}
				}
				System.out.println("");
			 }
			 System.out.println("");
			} for(int i = 1; i < parse.get(2*(n-1))+1; ++i){ //hight
				for(int j = 1; j < parse.get(2*n-1)+1; ++j){ //width
				if((i + j) % 2 == 0){
					System.out.print("#");
				}
				else if((i + j) % 2 != 0 ){
					System.out.print(".");
				}
				}
				System.out.println("");
			 } int i = 1; int i = 1; i 1 i < parse.get(2*(n-1))+1 i parse.get(2*(n-1))+1 parse.get(2*(n-1)) parse.get parse 2*(n-1) 2 (n-1) n 1 1 ++i ++i i { //hight
				for(int j = 1; j < parse.get(2*n-1)+1; ++j){ //width
				if((i + j) % 2 == 0){
					System.out.print("#");
				}
				else if((i + j) % 2 != 0 ){
					System.out.print(".");
				}
				}
				System.out.println("");
			 } { //hight
				for(int j = 1; j < parse.get(2*n-1)+1; ++j){ //width
				if((i + j) % 2 == 0){
					System.out.print("#");
				}
				else if((i + j) % 2 != 0 ){
					System.out.print(".");
				}
				}
				System.out.println("");
			 } for(int j = 1; j < parse.get(2*n-1)+1; ++j){ //width
				if((i + j) % 2 == 0){
					System.out.print("#");
				}
				else if((i + j) % 2 != 0 ){
					System.out.print(".");
				}
				} int j = 1; int j = 1; j 1 j < parse.get(2*n-1)+1 j parse.get(2*n-1)+1 parse.get(2*n-1) parse.get parse 2*n-1 2*n 2 n 1 1 ++j ++j j { //width
				if((i + j) % 2 == 0){
					System.out.print("#");
				}
				else if((i + j) % 2 != 0 ){
					System.out.print(".");
				}
				} { //width
				if((i + j) % 2 == 0){
					System.out.print("#");
				}
				else if((i + j) % 2 != 0 ){
					System.out.print(".");
				}
				} if((i + j) % 2 == 0){
					System.out.print("#");
				}
				else if((i + j) % 2 != 0 ){
					System.out.print(".");
				} (i + j) % 2 == 0 (i + j) % 2 (i + j) i j 2 0 {
					System.out.print("#");
				} System.out.print("#") System.out.print System.out System System.out "#" if((i + j) % 2 != 0 ){
					System.out.print(".");
				} (i + j) % 2 != 0 (i + j) % 2 (i + j) i j 2 0 {
					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 int exception(int h,int w){
			int result = 0;
			if(1 <= h && h <= 300 && 1 <= w && w <= 300){ //??????????????????(??\????¶???????)
				result = 2;
			}
			else if(h == 0 && w == 0){
				result = 1; //0,0??\?????§??\???????????????
			}
			else{
				System.out.println("1~300????????§.???????????????.");
				result = 0;
			}
			return result;
		}
		public static void main(String[] args) {
			/**
			 * ?????°?????£?¨?
			 */
			int a = 0;
			int t = 0, inc = 0;
			int h = 0,w = 0; //height:h width:w
			int x = 0;
			/**
			 * ???????????£?¨?
			 */
			ArrayList<String> st = new ArrayList<String>();
			ArrayList<Integer> parse = new ArrayList<Integer>();
			/**
			 * ????¨???????????????\???
			 */
			Scanner scan = new Scanner(System.in);
			while(a == 0){
			for (t = 0; t < 2; t++){ //??´??°2???????????????
			st.add(scan.next());
			}
			h = Integer.parseInt(st.get(inc));
			w = Integer.parseInt(st.get(inc+1));
			parse.add(h);
			parse.add(w);
			if(exception(h,w) == 1){ //h=w=0?????¨??????????????????????????????
				break;
			}
			else if(exception(h,w) == 0){ //??????????????????????????????.
				System.exit(0);
			}
			inc = inc + 2; //???????????§?????°
			}
			/**
			 * ??????
			 */
			for(int n= 1; n < ((parse.size())/2) ; ++n){ //???????????°??????
			 for(int i = 1; i < parse.get(2*(n-1))+1; ++i){ //hight
				for(int j = 1; j < parse.get(2*n-1)+1; ++j){ //width
				if((i + j) % 2 == 0){
					System.out.print("#");
				}
				else if((i + j) % 2 != 0 ){
					System.out.print(".");
				}
				}
				System.out.println("");
			 }
			 System.out.println("");
			}
		}
	} public class Main {
		public static int exception(int h,int w){
			int result = 0;
			if(1 <= h && h <= 300 && 1 <= w && w <= 300){ //??????????????????(??\????¶???????)
				result = 2;
			}
			else if(h == 0 && w == 0){
				result = 1; //0,0??\?????§??\???????????????
			}
			else{
				System.out.println("1~300????????§.???????????????.");
				result = 0;
			}
			return result;
		}
		public static void main(String[] args) {
			/**
			 * ?????°?????£?¨?
			 */
			int a = 0;
			int t = 0, inc = 0;
			int h = 0,w = 0; //height:h width:w
			int x = 0;
			/**
			 * ???????????£?¨?
			 */
			ArrayList<String> st = new ArrayList<String>();
			ArrayList<Integer> parse = new ArrayList<Integer>();
			/**
			 * ????¨???????????????\???
			 */
			Scanner scan = new Scanner(System.in);
			while(a == 0){
			for (t = 0; t < 2; t++){ //??´??°2???????????????
			st.add(scan.next());
			}
			h = Integer.parseInt(st.get(inc));
			w = Integer.parseInt(st.get(inc+1));
			parse.add(h);
			parse.add(w);
			if(exception(h,w) == 1){ //h=w=0?????¨??????????????????????????????
				break;
			}
			else if(exception(h,w) == 0){ //??????????????????????????????.
				System.exit(0);
			}
			inc = inc + 2; //???????????§?????°
			}
			/**
			 * ??????
			 */
			for(int n= 1; n < ((parse.size())/2) ; ++n){ //???????????°??????
			 for(int i = 1; i < parse.get(2*(n-1))+1; ++i){ //hight
				for(int j = 1; j < parse.get(2*n-1)+1; ++j){ //width
				if((i + j) % 2 == 0){
					System.out.print("#");
				}
				else if((i + j) % 2 != 0 ){
					System.out.print(".");
				}
				}
				System.out.println("");
			 }
			 System.out.println("");
			}
		}
	} Main
import java.util.ArrayList;
import java.util.Scanner;

public class Main {
		public static int exception(int h,int w){
			int result = 0;
			if(1 <= h && h <= 300 && 1 <= w && w <= 300){ //??????????????????(??\????¶???????)
				result = 2;
			}
			else if(h == 0 && w == 0){
				result = 1; //0,0??\?????§??\???????????????
			}
			else{
				System.out.println("1~300????????§.???????????????.");
				result = 0;
			}
			return result;
		}
		public static void main(String[] args) {
			/**
			 * ?????°?????£?¨?
			 */
			int a = 0;
			int t = 0, inc = 0;
			int h = 0,w = 0; //height:h width:w
			int x = 0;
			/**
			 * ???????????£?¨?
			 */
			ArrayList<String> st = new ArrayList<String>();
			ArrayList<Integer> parse = new ArrayList<Integer>();
			/**
			 * ????¨???????????????\???
			 */
			Scanner scan = new Scanner(System.in);
			while(a == 0){
			for (t = 0; t < 2; t++){ //??´??°2???????????????
			st.add(scan.next());
			}
			h = Integer.parseInt(st.get(inc));
			w = Integer.parseInt(st.get(inc+1));
			parse.add(h);
			parse.add(w);
			if(exception(h,w) == 1){ //h=w=0?????¨??????????????????????????????
				break;
			}
			else if(exception(h,w) == 0){ //??????????????????????????????.
				System.exit(0);
			}
			inc = inc + 2; //???????????§?????°
			}
			/**
			 * ??????
			 */
			for(int n= 1; n < ((parse.size())/2) ; ++n){ //???????????°??????
			 for(int i = 1; i < parse.get(2*(n-1))+1; ++i){ //hight
				for(int j = 1; j < parse.get(2*n-1)+1; ++j){ //width
				if((i + j) % 2 == 0){
					System.out.print("#");
				}
				else if((i + j) % 2 != 0 ){
					System.out.print(".");
				}
				}
				System.out.println("");
			 }
			 System.out.println("");
			}
		}
	}