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

W = int(W)
H = int(H)

if (C == 'B'):
    flag = 0
    FLAG = 0
else:
    flag = 1
    FLAG = 1

ichimatsu = []

for h in range(H):
    ichimatsu.append([])
    for w in range(W):
        if (flag == 0):
            ichimatsu[h].append('B')
            flag = 1
        else:
            ichimatsu[h].append('W')
            flag = 0
    if (FLAG == 0):
        FLAG = 1
        flag = 1
    else:
        FLAG = 0
        flag = 0

for h in range(H):
    print(''.join(ichimatsu[h]))