w,h,c=input().split()
h,w=int(h),int(w)
C='BW';c_index=C.index(c)
for i in range(h):
    s=''
    if i%2==0:
        c_index=C.index(c)
    else:
        c_index=1-C.index(c)
    for j in range(w):
        s+=C[c_index]
        c_index=1-c_index
    print(s)