main(){int a,d,i,j;scanf("%d",&d);for(i=0;i<d;++i){a=(i==d/2)?0:1;for(j=0;j<d;++j){if(j==i||j==d-i-1){printf("X");if(--a<0){printf("\n");break;}}else printf(" ");}}}
Note that non-ascii characters in the above source code will be escaped (such as \x9f).