#include<bits/stdc++.h>
// #include<atcoder/all>
// #include<boost/multiprecision/cpp_int.hpp>

using namespace std;
// using namespace atcoder;
// using bint = boost::multiprecision::cpp_int;
using ll = long long;
using ull = unsigned long long;
using P = pair<int,int>;
#define rep(i,n) for(ll i = 0;i < (ll)n;i++)
#define ALL(x) (x).begin(),(x).end()
#define MOD 1000000007
// #define MOD 998244353


int main(){
  
  ll n,K;
  cin >> n >> K;
  vector<string> s(2*n);
  rep(i,2*n)cin >> s[i];
  vector<vector<ll>> c(2*n,vector<ll>(2*n));
  vector<ll> v(4*n*n);
  rep(i,2*n)rep(j,2*n)cin >> c[i][j],v[i*2*n + j] = c[i][j];
  int cnt = 0;
  rep(i,2*n)rep(j,2*n)cnt += (s[i][j] == '#');
  ll res = 0;
  if(cnt%2 == 0){
    vector<ll> g(4*n*n,-(1ll << 60));
    rep(i,2*n)rep(j,n)g[i*2*n + j] = c[i][j] + c[i][2*n-j-1];
    sort(ALL(g),greater<ll>());
    rep(i,cnt/2)res += g[i];
    res += K;
  }
  sort(ALL(v),greater<ll>());
  ll ans = 0;
  rep(i,cnt)ans += v[i];
  cout << max(res,ans)  << "\n";


  

  return 0;
}