W,H,C = input().split()
W=int(W)
H=int(H)

def reverse_c(color):
    if color == "B":
        return "W"
    else:
        return "B"

for h in range(H):
    if h%2 == 0:
        ct=C
    else:
        ct=reverse_c(C)
    tmp=""
    for w in range(W):
        if w%2==0:
            tmp+=ct
        else:
            tmp+=reverse_c(ct)
    print(tmp)