#include<stdio.h>
#include<stdlib.h>
#include<string.h>
#include<math.h>

typedef long long int ll;

ll MAX(ll a, ll b){return a>b?a:b;}
ll MIN(ll a, ll b){return a>b?b:a;}
int compare(const void* a, const void* b){return *(int*)a - *(int*)b;}
ll digits(ll a){ll tmp=a; ll cnt=0; while(tmp>0){tmp/=10; cnt+=1;} return cnt;}

int main(void){
    int w,h;
    char c;
    scanf("%d %d %c", &w,&h,&c);

    char start_b[w+1];
    char start_w[w+1];
    for(int i=0; i<w; i++){
        if(i%2==0){
            start_b[i] = 'B';
            start_w[i] = 'W';
        }else{
            start_b[i] = 'W';
            start_w[i] = 'B';
        }
    }
    start_b[w]='\0';
    start_w[w]='\0';
    
    if(start_b[0] == c){
        for(int i=0; i<h; i++){
            if(i%2==0){
                printf("%s\n", start_b);
            }else{
                printf("%s\n", start_w);
            }
        }
    }else{
        for(int i=0; i<h; i++){
            if(i%2==0){
                printf("%s\n", start_w);
            }else{
                printf("%s\n", start_b);
            }
        }
    }

    return 0;
}