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

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

  bool t;
  if(C == "B") {
    t = false;
  } else {
    t = true;
  }

  foreach(int i; 0 .. H) {
    foreach(int j; 0 .. W) {
      write(((i+j)%2 == t)?"B":"W");
    }
    writeln();
  }


}