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

void main()
{
  auto rd = readln.split;
  auto w = rd[0].to!int;
  auto h = rd[1].to!int;
  auto c = rd[2];

  foreach (i; 0..h) {
    writeLine(w, c);
    c = rev(c);
  }
}

void writeLine(int w, string c)
{
  foreach (i; 0..w) {
    write(c);
    c = rev(c);
  }
  writeln;
}

string rev(string c)
{
  return c == "B" ? "W" : "B";
}