#include <bits/stdc++.h>
//#include <atcoder/all>
using namespace std;
//using namespace atcoder;
//using mint = modint1000000007;
//const int mod = 1000000007;
//using mint = modint998244353;
//const int mod = 998244353;
//const int INF = 1e9;
const long long LINF = 1e18;
#define rep(i, n) for (int i = 0; i < (n); ++i)
#define rep2(i,l,r)for(int i=(l);i<(r);++i)
#define rrep(i, n) for (int i = (n-1); i >= 0; --i)
#define rrep2(i,l,r)for(int i=(r-1);i>=(l);--i)
#define all(x) (x).begin(),(x).end()
#define allR(x) (x).rbegin(),(x).rend()
#define endl "\n"
#define P pair<int,int>
template<typename A, typename B> inline bool chmax(A & a, const B & b) { if (a < b) { a = b; return true; } return false; }
template<typename A, typename B> inline bool chmin(A & a, const B & b) { if (a > b) { a = b; return true; } return false; }

int main() {
	ios::sync_with_stdio(false);
	cin.tie(nullptr);
	int n; cin >> n; n *= 2;
	long long k; cin >> k;
	vector<string>s(n);
	rep(i, n)cin >> s[i];
	vector<vector<long long>> data(n, vector<long long>(n));
	rep(i, n)rep(j, n)cin >> data[i][j];
	int cnt = 0;
	vector<long long>v;
	vector<long long>v2;
	rep(i, n)rep(j, n) {
		v.push_back(data[i][j]);
		int nj = n - 1 - j;
		if (j <= nj)v2.push_back(data[i][j] + data[i][nj]);
		if ('#' == s[i][j])cnt++;
	}
	sort(allR(v));
	sort(allR(v2));
	long long ans = -LINF;
	{
		long long sub = 0;
		rep(i, cnt) sub += v[i];
		chmax(ans, sub);
	}
	if (0 == cnt % 2) {
		long long sub = k;
		rep(i, cnt / 2)sub += v2[i];
		chmax(ans, sub);
	}
	cout << ans << endl;
	return 0;
}