#include    <stdio.h>

int main(void)
{
    int     W, H;
    char    C;
    int     x, y;
    char    a[2] = { 'B', 'W' };
    int     b, c;

    scanf("%d %d %c", &W, &H, &C);
    b = ((C == 'B') ? 0 : 1);

    for (y = 0; y < H; y++) {
        c = b ^ (y & 1);
        for (x = 0; x < W; x++) {
            putchar(a[c]);
            c ^= 1;
        }
        putchar('\n');
    }

    return 0;
}