
import java.util.*;

class Main{
public static void main(String[] args){
Scanner sc = new Scanner(System.in);
int W,H;
for(;;){
H =sc.nextInt();
W =sc.nextInt();
if(H == 0) break;
for(int b=1; b<=H; b++){
if(b%2 ==0){
for(int a=1; a<=W; a++){
if(a%2 ==0) System.out.print("#");
else System.out.print(".");
}System.out.println();
}else{
for(int a=1; a<=W; a++){
if(a%2 ==0) System.out.print(".");
else System.out.print("#");
}
System.out.println();
}
}
System.out.println();
}
}
} import java.util.*; util.* java class Main{
public static void main(String[] args){
Scanner sc = new Scanner(System.in);
int W,H;
for(;;){
H =sc.nextInt();
W =sc.nextInt();
if(H == 0) break;
for(int b=1; b<=H; b++){
if(b%2 ==0){
for(int a=1; a<=W; a++){
if(a%2 ==0) System.out.print("#");
else System.out.print(".");
}System.out.println();
}else{
for(int a=1; a<=W; a++){
if(a%2 ==0) System.out.print(".");
else System.out.print("#");
}
System.out.println();
}
}
System.out.println();
}
}
} Main public static void main(String[] args){
Scanner sc = new Scanner(System.in);
int W,H;
for(;;){
H =sc.nextInt();
W =sc.nextInt();
if(H == 0) break;
for(int b=1; b<=H; b++){
if(b%2 ==0){
for(int a=1; a<=W; a++){
if(a%2 ==0) System.out.print("#");
else System.out.print(".");
}System.out.println();
}else{
for(int a=1; a<=W; a++){
if(a%2 ==0) System.out.print(".");
else System.out.print("#");
}
System.out.println();
}
}
System.out.println();
}
} main {
Scanner sc = new Scanner(System.in);
int W,H;
for(;;){
H =sc.nextInt();
W =sc.nextInt();
if(H == 0) break;
for(int b=1; b<=H; b++){
if(b%2 ==0){
for(int a=1; a<=W; a++){
if(a%2 ==0) System.out.print("#");
else System.out.print(".");
}System.out.println();
}else{
for(int a=1; a<=W; a++){
if(a%2 ==0) System.out.print(".");
else System.out.print("#");
}
System.out.println();
}
}
System.out.println();
}
} Scanner sc = new Scanner(System.in); sc new Scanner(System.in) int W W H; H for(;;){
H =sc.nextInt();
W =sc.nextInt();
if(H == 0) break;
for(int b=1; b<=H; b++){
if(b%2 ==0){
for(int a=1; a<=W; a++){
if(a%2 ==0) System.out.print("#");
else System.out.print(".");
}System.out.println();
}else{
for(int a=1; a<=W; a++){
if(a%2 ==0) System.out.print(".");
else System.out.print("#");
}
System.out.println();
}
}
System.out.println();
} ; {
H =sc.nextInt();
W =sc.nextInt();
if(H == 0) break;
for(int b=1; b<=H; b++){
if(b%2 ==0){
for(int a=1; a<=W; a++){
if(a%2 ==0) System.out.print("#");
else System.out.print(".");
}System.out.println();
}else{
for(int a=1; a<=W; a++){
if(a%2 ==0) System.out.print(".");
else System.out.print("#");
}
System.out.println();
}
}
System.out.println();
} {
H =sc.nextInt();
W =sc.nextInt();
if(H == 0) break;
for(int b=1; b<=H; b++){
if(b%2 ==0){
for(int a=1; a<=W; a++){
if(a%2 ==0) System.out.print("#");
else System.out.print(".");
}System.out.println();
}else{
for(int a=1; a<=W; a++){
if(a%2 ==0) System.out.print(".");
else System.out.print("#");
}
System.out.println();
}
}
System.out.println();
} H =sc.nextInt() H sc.nextInt() sc.nextInt sc W =sc.nextInt() W sc.nextInt() sc.nextInt sc if(H == 0) break; H == 0 H 0 break; for(int b=1; b<=H; b++){
if(b%2 ==0){
for(int a=1; a<=W; a++){
if(a%2 ==0) System.out.print("#");
else System.out.print(".");
}System.out.println();
}else{
for(int a=1; a<=W; a++){
if(a%2 ==0) System.out.print(".");
else System.out.print("#");
}
System.out.println();
}
} int b=1; int b=1; b 1 b<=H b H b++ b++ b {
if(b%2 ==0){
for(int a=1; a<=W; a++){
if(a%2 ==0) System.out.print("#");
else System.out.print(".");
}System.out.println();
}else{
for(int a=1; a<=W; a++){
if(a%2 ==0) System.out.print(".");
else System.out.print("#");
}
System.out.println();
}
} {
if(b%2 ==0){
for(int a=1; a<=W; a++){
if(a%2 ==0) System.out.print("#");
else System.out.print(".");
}System.out.println();
}else{
for(int a=1; a<=W; a++){
if(a%2 ==0) System.out.print(".");
else System.out.print("#");
}
System.out.println();
}
} if(b%2 ==0){
for(int a=1; a<=W; a++){
if(a%2 ==0) System.out.print("#");
else System.out.print(".");
}System.out.println();
}else{
for(int a=1; a<=W; a++){
if(a%2 ==0) System.out.print(".");
else System.out.print("#");
}
System.out.println();
} b%2 ==0 b%2 b 2 0 {
for(int a=1; a<=W; a++){
if(a%2 ==0) System.out.print("#");
else System.out.print(".");
}System.out.println();
} for(int a=1; a<=W; a++){
if(a%2 ==0) System.out.print("#");
else System.out.print(".");
} int a=1; int a=1; a 1 a<=W a W a++ a++ a {
if(a%2 ==0) System.out.print("#");
else System.out.print(".");
} {
if(a%2 ==0) System.out.print("#");
else System.out.print(".");
} if(a%2 ==0) System.out.print("#");
else System.out.print("."); a%2 ==0 a%2 a 2 0 System.out.print("#") System.out.print System.out System System.out "#" System.out.print(".") System.out.print System.out System System.out "." System.out.println() System.out.println System.out System System.out {
for(int a=1; a<=W; a++){
if(a%2 ==0) System.out.print(".");
else System.out.print("#");
}
System.out.println();
} for(int a=1; a<=W; a++){
if(a%2 ==0) System.out.print(".");
else System.out.print("#");
} int a=1; int a=1; a 1 a<=W a W a++ a++ a {
if(a%2 ==0) System.out.print(".");
else System.out.print("#");
} {
if(a%2 ==0) System.out.print(".");
else System.out.print("#");
} if(a%2 ==0) System.out.print(".");
else System.out.print("#"); a%2 ==0 a%2 a 2 0 System.out.print(".") System.out.print System.out System System.out "." 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

import java.util.*;

class Main{
public static void main(String[] args){
Scanner sc = new Scanner(System.in);
int W,H;
for(;;){
H =sc.nextInt();
W =sc.nextInt();
if(H == 0) break;
for(int b=1; b<=H; b++){
if(b%2 ==0){
for(int a=1; a<=W; a++){
if(a%2 ==0) System.out.print("#");
else System.out.print(".");
}System.out.println();
}else{
for(int a=1; a<=W; a++){
if(a%2 ==0) System.out.print(".");
else System.out.print("#");
}
System.out.println();
}
}
System.out.println();
}
}
}