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

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

cloth = ""

for i in range(h):
    for j in range(w):
        cloth += c
        if c == "B":
            c = "W"
        else:
            c = "B"
    cloth += "\n"
    if( w % 2 == 0 ):
        if c == "B":
            c = "W"
        else:
            c = "B"

print(cloth)