import java.util.*;
import java.io.*;
public class OriginOfLife {

	static boolean[][] holder;
	static boolean[][] life;
	static boolean[] generated;
	static int row, col;
	static ArrayList<ArrayList<Integer>> prev = new ArrayList<ArrayList<Integer>>();

	static int count(int r, int c) {
		int count = 0;
		for(int i = r - 1; i <= r + 1; i ++) {
			for(int j = c - 1; j <= c + 1; j ++) {
				try {
					if(holder[i][j]) {
						count ++;
					}
				}catch(ArrayIndexOutOfBoundsException e) {}
			}
		}
		if(holder[r][c]) {
			count -= 1;
		}
		return count;

	}

	static void generate(int l, int a, int b, int c) {
		if(generated[l]) {
			return;
		}
		toHolder(l);
		for(int i = 0; i < row; i ++) {
			for(int j = 0; j < col; j ++) {
				int count = count(i, j);
				if(holder[i][j]) {
					if(count < a || count > b) {
						life[i][j] = false;
					}else {
						life[i][j] = holder[i][j];
					}
				}else {
					if(count > c) {
						life[i][j] = true;
					}else {
						life[i][j] = holder[i][j];
					}
				}
			}
		}
		boolean[][] placeholder = holder;
		int next = toInt(life);
		prev.get(next).add(l);
		holder = life;
		life = placeholder;
		generated[l] = true;
		generate(next, a, b, c);
	}

	static void toHolder(int l) {
		int m = 1;

		for(int i = 0; i < row; i ++) {
			for(int j = 0; j < col; j ++) {
				if((l & m) != 0) {
					holder[i][j] = true;
				}else {
					holder[i][j] = false;
				}
				m <<= 1;
			}
		}
	}

	static int toInt(boolean[][] ar) {
		int ret = 0;
		for(int i = row - 1; i >= 0; i --) {
			for(int j = col - 1; j >= 0; j --) {
				ret <<= 1;
				if(ar[i][j]) {
					ret += 1;
				}
			}
		}
		return ret;
	}

	static int bfs(int input) {
		Queue<Integer> q = new LinkedList<Integer>();
		q.add(input);
		int step = 0;
		while(!q.isEmpty()) {
			int size = q.size();
			for(int i = 0; i < size; i ++) {
				int curr = q.poll();
				if(generated[curr]) {
					continue;
				}
				generated[curr] = true;
				if(prev.get(curr).isEmpty()) {
					return step;
				}else {
					for(int v : prev.get(curr)) {
						q.add(v);
					}
				}
			}
			step ++;
		}
		return -1;
	}

	public static void main(String[] args) throws IOException{
		BufferedReader in = new BufferedReader(new InputStreamReader(System.in));
		StringTokenizer st = new StringTokenizer(in.readLine());
		row = Integer.parseInt(st.nextToken());
		col = Integer.parseInt(st.nextToken());
		int a = Integer.parseInt(st.nextToken());
		int b = Integer.parseInt(st.nextToken());
		int c = Integer.parseInt(st.nextToken());
		holder = new boolean[row][col];
		life = new boolean[row][col];
		generated = new boolean[(int) 1 << (row * col)];

		for(int i = 0; i < 1 << (row * col); i ++) {
			prev.add(new ArrayList<Integer>());
		}
		for(int i = 0; i < 1 << (row * col); i ++) {
			generate(i, a, b, c);
		}

		for(int i = 0; i < row; i ++) {
			String inp = in.readLine();
			for(int j = 0; j < col; j ++) {
				holder[i][j] = inp.charAt(j) == '*';
			}
		}
		Arrays.fill(generated, false);
		int input = toInt(holder);
		System.out.println(bfs(input));
	}
}