#include<iostream>
#include<string>
#include<cstring>
#include<complex>
#include<vector>
#include<algorithm>
#include<cstdlib>
#include<cmath>
#include<iomanip>
using namespace std;

#define REP(i, j) for (int i = 0; i < (int)j; ++i)
#define FOR(i, j, k) for (int i = (int)j; i < (int)k; ++i)
#define SORT(v) sort(v.begin(), v.end())
#define REVERSE(v) reverse(v.begin(), v.end())
typedef complex<double> P;
typedef vector<int> VI;
typedef long long LL;
typedef pair<int,int> PII;

int main() {
	cin.tie(0);
	ios::sync_with_stdio(false);

	int w, h;
	char c;
	cin >> w >> h >> c;

	REP(i,h) {
		REP(j,w) {
			cout << c;
			c = (c == 'B' ? 'W' : 'B');
			if (j == (w - 1) && (w % 2) == 0) {
				c = (c == 'B' ? 'W' : 'B');
			}
		}
		cout << endl;
	}

	return 0;
}