# -*- coding: utf-8 -*-

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

patterns = ['','']
for i in range(25):
    patterns[0] += 'BW'
    patterns[1] += 'WB'

init = 0 if C=='B' else 1

for i in range(H):
    row = ''
    row = patterns[init%2][:W]
    init += 1
    print(row)