#include <cstdio>
#include <algorithm>
using namespace std;
const int N = 1005;
int n, m, r, c, sx, sy, ex, ey;
char s[N][N];
int col[N][N];
int dx[] = {1, 1, -1, -1};
int dy[] = {1, -1, 1, -1};
void dfs1 (int x, int y, int ch) {
	col[x][y] = ch;
	for (int i = 0; i < 4; i++) {
		int nx = x + dx[i] * r, ny = y + dy[i] * c;
		if (1 <= nx && nx <= n && 1 <= ny && ny <= m && s[nx][ny] != '@' && !col[nx][ny]) {
			dfs1 (nx, ny, 3 - ch);
		} 
	}
	for (int i = 0; i < 4; i++) {
		int nx = x + dx[i] * c, ny = y + dy[i] * r;
		if (1 <= nx && nx <= n && 1 <= ny && ny <= m && s[nx][ny] != '@' && !col[nx][ny]) {
			dfs1 (nx, ny, 3 - ch);
		} 
	}
}
int sz;
bool vis[N][N];
int main() {
	scanf ("%d%d%d%d", &n, &m, &r, &c);
	for (int i = 1; i <= n; i++) {
		scanf ("%s", s[i] + 1);
		for (int j = 1; j <= m; j++) {
			if (s[i][j] == 'A') sx = i, sy = j;
			if (s[i][j] == 'B') ex = i, ey = j;
		}
	}
	for (int i = 1; i <= n; i++) {
		for (int j = 1; j <= m; j++) {
			if (!col[i][j] && s[i][j] != '@') dfs1 (i, j, 1);		
		}
	}
	return 0;
}