#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using ld = long double;
using pcc = pair<char,char>;
using pii = pair<int,int>;
using pll = pair<ll,ll>;
using pdd = pair<ld,ld>;
using tuplis = array<ll,3>;
template<class T> using prique = priority_queue<T,vector<T>,greater<T>>;
#define rep(i,n) for(ll i = 0; i < n; i++)
#define rrep(i,n) for(ll i = n-1; i >= 0; i--)
#define all(a) a.begin(),a.end()
#define rall(a) a.rbegin(),a.rend()
#define Sort(a) sort(all(a))
#define Rev(a) reverse(all(a))
#define Uniq(a) sort(all(a));a.erase(unique(all(a)),a.end())
const ll LINF = 1001001001001001001;
const int INF = 1001001001;
const int MOD = 1000000007;
const int MODD = 998244353;
const ld PI = 3.1415926535897932;
const ll dx[] = {0, 1, 0, -1, 1, -1, 1, -1};
const ll dy[] = {1, 0, -1, 0, 1, 1, -1, -1};
inline ll popcnt(ll a){ return __builtin_popcountll(a); }
inline ll intpow(ll a, ll b){ ll ans = 1; while(b){ if(b & 1) ans *= a; a *= a; b /= 2; } return ans; }
inline ll modpow(ll a, ll b, ll p){ ll ans = 1; while(b){ if(b & 1) (ans *= a) %= p; (a *= a) %= p; b /= 2; } return ans; }
ll gcd(ll a,ll b){ if(a%b == 0){return b; } else{ return gcd(b,a%b); } }
ll lcm(ll a,ll b){ return a/gcd(a,b)*b; }
template<class T> bool chmin(T& a, const T& b){ if(a > b){ a = b; return 1; } return 0; }
template<class T> bool chmax(T& a, const T& b){ if(a < b){ a = b; return 1; } return 0; }
template<class T, class U> bool chmin(T& a, const U& b){ if(a > T(b)){ a = b; return 1; } return 0; }
template<class T, class U> bool chmax(T& a, const U& b){ if(a < T(b)){ a = b; return 1; } return 0; }
int main() {
    int W,H;
    char C;
    cin >> W >> H >> C;
    rep(i,H) {
        rep(j,W) {
            if((i+j)%2 == 0) {
                cout << C;
            }
            else {
                cout << ((C == 'B')?'W':'B');
            }
        }
        cout << endl;
    }
}