import std.conv, std.functional, std.range, std.stdio, std.string;
import std.algorithm, std.array, std.bigint, std.bitmanip, std.complex, std.container, std.math, std.mathspecial, std.numeric, std.regex, std.typecons;
import core.bitop;

class EOFException : Throwable { this() { super("EOF"); } }
string[] tokens;
string readToken() { for (; tokens.empty; ) { if (stdin.eof) { throw new EOFException; } tokens = readln.split; } auto token = tokens.front; tokens.popFront; return token; }
int readInt() { return readToken.to!int; }
long readLong() { return readToken.to!long; }
real readReal() { return readToken.to!real; }

bool chmin(T)(ref T t, in T f) { if (t > f) { t = f; return true; } else { return false; } }
bool chmax(T)(ref T t, in T f) { if (t < f) { t = f; return true; } else { return false; } }

int binarySearch(alias pred, T)(in T[] as) { int lo = -1, hi = cast(int)(as.length); for (; lo + 1 < hi; ) { const mid = (lo + hi) >> 1; (unaryFun!pred(as[mid]) ? hi : lo) = mid; } return hi; }
int lowerBound(T)(in T[] as, T val) { return as.binarySearch!(a => (a >= val)); }
int upperBound(T)(in T[] as, T val) { return as.binarySearch!(a => (a > val)); }




void main() {
  try {
    for (; ; ) {
      const N = 2 * readInt;
      const K = readLong;
      auto S = new string[N];
      foreach (x; 0 .. N) {
        S[x] = readToken;
      }
      auto C = new long[][](N, N);
      foreach (x; 0 .. N) foreach (y; 0 .. N) {
        C[x][y] = readLong;
      }
      
      int paint;
      foreach (x; 0 .. N) foreach (y; 0 .. N) if (S[x][y] == '#') {
        ++paint;
      }
      
      long ans = long.min;
      {
        long[] cs;
        foreach (x; 0 .. N) foreach (y; 0 .. N) {
          cs ~= C[x][y];
        }
        cs.sort!"a > b";
        const score = cs[0 .. paint].sum;
        chmax(ans, score);
      }
      
      if (paint % 2 == 0) {
        long[] cs;
        foreach (x; 0 .. N) foreach (y; 0 .. N / 2) {
          cs ~= C[x][y] + C[x][N - 1 - y];
        }
        cs.sort!"a > b";
        const score = K + cs[0 .. paint / 2].sum;
        chmax(ans, score);
      }
      writeln(ans);
    }
  } catch (EOFException e) {
  }
}