# coding: utf-8
# Your code here!

def solve():
    w, h, c = input().split()
    if c == "W":
        start = c
        next_c = "B"
    else:
        start = c
        next_c = "W"
    
    for i in range(int(h)):
        print("".join([start if i % 2 == 0 else next_c for i in range(int(w))]))
        tmp = start
        start = next_c
        next_c = tmp

if __name__ == "__main__":
    solve()