W,H,C=input(). split ()
W=int(W)
H=int(H)
if C=="B":
    D="W"
else:
    D="B"
Bo=[[C]*W]*H
for i in range (H):
    for i in range (W):
        N=i+j
        if N%2==1:
            Bo[i][j]=D
for i in range (H):
    print("".join(Bo[i]))