n,m,c = input().split()

if c == "W":
    v = "B"
else:
    v = "w"
for j in range(int(m)):
    for i in range(int(n)):
        if i % 2 != 0: 
            print(v,end="")
        if i % 2 == 0:
            print(c,end="")
    v,c = c,v
    print()