let input = readLine()!.split(separator: " ")
let W = Int(input[0])
let H = Int(input[1])
var C = input[2]
for _ in 1...H!{
    var D = C
    for _ in 1...W!{
        print(D,terminator: "")
        D = (D == "W" ? "B" : "W" )
    }
    print()
    C = (C == "W" ? "B" : "W" )
}