function Main(input) {
    'use strict';
    var MAX = 50;

    var inputArr = input.split('\n')[0].split(' ');
    var w = +inputArr[0];
    var h = +inputArr[1];
    var char0 = (inputArr[2] === 'W') ? 'W' : 'B';
    var char1 = (inputArr[2] === 'W') ? 'B' : 'W';

    var arrLine = new Array(MAX);
    var line0 = arrLine.join(char0 + char1).slice(0,w) + '\n';
    var line1 = arrLine.join(char1 + char0).slice(0,w) + '\n';
    var delimiter = '|'

    var tmp = (new Array(MAX)).join(line0+delimiter).split(delimiter).join(line1);

    var ans = tmp.slice(0, (w+1)*h);

    console.log(ans);
}

// Don't edit this line!
Main(require("fs").readFileSync("/dev/stdin", "utf8"));