import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.util.Collections;
import java.util.PriorityQueue;

public class Main {
	public static void main(String[] args) throws Exception {
		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
		String[] sa = br.readLine().split(" ");
		int n = Integer.parseInt(sa[0]);
		long k = Long.parseLong(sa[1]);
		int n2 = n * 2;
		char[][] s = new char[n2][n2];
		for (int i = 0; i < n2; i++) {
			s[i] = br.readLine().toCharArray();
		}
		int[][] c = new int[n2][n2];
		for (int i = 0; i < n2; i++) {
			sa = br.readLine().split(" ");
			for (int j = 0; j < n2; j++) {
				c[i][j] = Integer.parseInt(sa[j]);
			}
		}
		br.close();

		int b = 0;
		for (int i = 0; i < n2; i++) {
			for (int j = 0; j < n2; j++) {
				if (s[i][j] == '#') {
					b++;
				}
			}
		}

		PriorityQueue<Integer> que1 = new PriorityQueue<>(Collections.reverseOrder());
		PriorityQueue<Integer> que2 = new PriorityQueue<>(Collections.reverseOrder());
		for (int i = 0; i < n2; i++) {
			for (int j = 0; j < n2; j++) {
				que1.add(c[i][j]);
			}
			for (int j = 0; j < n; j++) {
				que2.add(c[i][j] + c[i][n2 - 1 - j]);
			}
		}

		long ans = 0;
		for (int i = 0; i < b; i++) {
			ans += que1.poll();
		}

		if (b % 2 == 0) {
			int b2 = b / 2;
			long val = 0;
			for (int i = 0; i < b2; i++) {
				val += que2.poll();
			}
			ans = Math.max(ans, val + k);
		}
		System.out.println(ans);
	}
}