#include <bits/stdc++.h>
#include <sys/time.h>


using namespace std;


using ll = long long;
using ull = unsigned long long;
using ld = long double;
using vi = vector<int>;
using vvi = vector<vi>;
using vvvi = vector<vvi>;
using vl = vector<long>;
using vvl = vector<vl>;
using vll = vector<ll>;
using vvll = vector<vll>;
using vb = vector<bool>;
using vvb = vector<vb>;
using pii = pair<int, int>;
using pll = pair<ll, ll>;
using vpii = vector<pii>;
using vpll = vector<pll>;
using vstr = vector<string>;
constexpr ll INF_LL=1LL<<62;
constexpr int INF_I=1LL<<30;
#define rep(i,n) for(int i=0; i<((int)(n)); i++)
#define reps(i,n) for(int i=1; i<=((int)(n)); i++)
#define vector_cin(x) for(auto &n : (x)) cin >> n
#define ALL(x) (x).begin(), (x).end()
#define YesNo(x) ((x) ? "Yes": "No")
#define pb emplace_back
#define to_lower(S) transform(ALL((S)), (S).begin(), ::tolower)
#define to_upper(S) transform(ALL((S)), (S).begin(), ::toupper)
template <typename T>
bool chmax(T &a, const T& b) {if (a < b){a = b;return true;}return false;}

template <typename T>
bool chmin(T &a, const T& b) {if (a > b){a = b;return true;}return false;}
ll ceilint(ll x, ll y) {return (x + y - 1) / y;}
void Main();
int main() {std::cin.tie(nullptr);std::ios_base::sync_with_stdio(false);std::cout << std::fixed << std::setprecision(15);Main();return 0;}

//-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-

void Main() {
    ll N, K;
    cin >> N >> K;
    vstr S(N * 2);
    vector_cin(S);
    vvll C(2 * N, vll(2 * N));
    priority_queue<ll> white;
    priority_queue<ll> sum;
    ll ans = 0, size_b = 0, size_w = 0;
    rep(i, 2 * N)
        rep(j, 2 * N)
            cin >> C[i][j];
    rep(i, 2 * N) {
        rep(j, 2 * N) {
            if (S[i][j] == '#') {
                size_b++;
            } else {
                size_w++;
            }
            if (j <= N - 1) {
                sum.push(C[i][j] + C[i][2 * N - j - 1]);
            }
            white.push(C[i][j]);
        }
    }
    ans = 0;
    rep(i, size_b) ans += white.top(), white.pop();
    ll num = -INF_LL;
    if (size_b % 2 == 0) {
        num = 0;
        rep(i, size_b / 2) num += sum.top(), sum.pop();
        num += K;
    }
    
    cout << max(ans, num) << endl;
}