const writeRow = (n: number, start: string) => {
    const second: string = start === 'W' ? 'B' : 'W';
    let result = start;
    for (let i = 0; i < n; i++) {
        if (i % 2 == 0) result += second;
        if (i % 2 !== 0) result += start;
    }
    return result
}

const Main = (input) => {
    const data = input.split("\n")
    const width: number = data[0], heigh: number = data[1];
    const start: string = data[2];
    let result = '';
    const row = writeRow(width, start);
    for (var i = 1; i <= heigh; i++) {
        result += `${row}`
        if (i < heigh) result += `\n`
    }
    console.log(result);
}

Main(require("fs").readFileSync("/dev/stdin", "utf8"));