w, h, c = input().split()
w = int(w)
h = int(h)

ANS = [['' for _ in range(w)] for _ in range(h)]
cc = c
for i in range(h):
    if i % 2 == 0:
        cc = c
    else:
        if c == 'W':
            cc = 'B'
        else:
            cc = 'W'
    for j in range(w):
        ANS[i][j] = cc
        if cc == 'W':
            cc = 'B'
        else:
            cc = 'W'
for i in range(h):
    print(''.join(ANS[i]))