w,h,c = map(str, input().split())
w,h = int(w), int(h)
if c == 'B':
    ans = [[0]*w for _ in range(h)]
    for i in range(h):
        for j in range(w):
            if (i+j)%2 == 0:
                ans[i][j] = 'B'
            else:
                ans[i][j] = 'W'
else:
    ans = [[0]*w for _ in range(h)]
    for i in range(h):
        for j in range(w):
            if (i+j)%2 == 0:
                ans[i][j] = 'W'
            else:
                ans[i][j] = 'B'
for i in range(h):
    print(''.join(ans[i]))