a,c,e;main(){;scanf("%i",&a);char b[a*a*a],*d;memset(d=b,' ',a*a*a);for(;c<a-1;d+=a-c-2,memset(d,'*',e=2*c+1),d+=e,memset(d++,'\n',1),c++);strcpy(d+a-3,"G*F\0");puts(b);}
Note that non-ascii characters in the above source code will be escaped (such as \x9f).