f=lambda n,s=" _":n*" "and f(n-1,"").join([s,"_"*(n-2)+"\n%c|%s|"%(64+n,"_"*n),""])
f=lambda n,s=' _':n and f(n-1,s)+"_"*(n-2)+"\n%c|%s|"%(64+n,"_"*n)+f(n-1,'')or s