w,h,c=input().split() if c=="B": d="BC" e="C" f="CB" else: d="CB" e="B" f="BC" w=int(w) h=int(h) a=w%2 b=w//2 if a==1: s=d*b+c t=f*b+e else: s=d*b t=f*b p=h%2 q=h//2 if p==1: for i in range(q): print(s) print(t) print(t) else: for i in range(q): print(s) print(t)