Codeforces Round #290 (Div. 2)

 1 #include<cstdio>
 2 int main()
 3 {
 4     int n,m;
 5     while(scanf("%d%d",&n,&m)!=EOF){
 6         for(int i=1;i<=n;i++){
 7             if(i%4==1||i%4==3){
 8                 for(int j=1;j<=m;j++)
 9                     printf("#");
10                 printf("\n");
11             }
12             else if(i%4){
13                 for(int j=1;j<m;j++)
14                     printf(".");
15                 printf("#\n");
16             }
17             else{
18                 printf("#");
19                 for(int j=2;j<=m;j++)
20                     printf(".");
21                 printf("\n");
22             }
23         }
24     }
25     return 0;
26 }