import std.stdio,
       std.conv,
       std.string,
       std.range,
       std.math,
       std.algorithm;

void main()
{
    auto input = readln.split;
    auto W = input[0].to!int, H = input[1].to!int;
    auto C = input[2];

    auto cur = (C == "B" ? 0 : 1);
    auto color = ["B", "W"];
    foreach (h; 0 .. H)
    {
        foreach (w; 0 .. W)
        {
            color[cur].write;
            cur = (cur + 1) % 2;
        }
        writeln;
        cur = (cur + W + 1) % 2;
    }
}