import sequtils,strutils,strscans
var
    W,H : int
    C : string
    a,b : string
    L = stdin.readline
discard scanf(L,"$i $i $+\n",W, H, C)

a = repeat("BW",(W + 1) div 2)
b = repeat("WB",(W + 1) div 2)
if C == "W":
    (a,b) = (b,a)
for i in 1..H:
    if (i and 1) == 1:
        echo a[0..<W]
    else:
        echo b[0..<W]