#include<bits/stdc++.h>
using namespace std;
#define int long long
const int maxn = 505;
int n,k;
int cnt;
bitset<maxn> vis[maxn];
int gr[maxn][maxn];
class node{
    public:
    int x,y,val;
    node(){}
    node(int _x,int _y,int _val):x(_x),y(_y),val(_val){}
    friend bool operator<(node a,node b){return a.val < b.val;}
};
priority_queue<node> pq;
priority_queue<node> fpq;
int solve1(){
    int localk = cnt;
    if(localk&1)return numeric_limits<long long>::min();
    localk>>=1;
    int fans = 0;
    for(int i = 0;i<=n;++i)vis[i] = 0;
    while(localk){
        localk -= 1;
        auto ed = fpq.top();
        fpq.pop();
        vis[ed.x][ed.y] = 1;
        fans += ed.val;
    }
    return fans+k;
}
int solve2(){
    for(int i = 0;i<=n;++i)vis[i] = 0;
    int localk = cnt;
    int fans = 0;
    while(localk){
        localk-=1;
        auto ed = pq.top();
        pq.pop();
        vis[ed.x][ed.y] = 1;
        fans += ed.val;
    }
    return fans;
}
signed main(){
    cin >> n >> k;
    n *= 2;
    char ch;
    for(int i = 0;i<n;++i)
        for(int j = 0;j<n;++j){
            cin >> ch;
            if(ch == '#')cnt++;
    }
    for(int i = 1;i<=n;++i){
        for(int j = 1;j<=n;++j){
            cin >> gr[i][j];
            pq.push(node(i,j,gr[i][j]));
        }
    }
    for(int i = 1;i<=n;++i){
        for(int j = 1;j<=n>>1;++j){
            fpq.push(node(i,j,gr[i][j] + gr[i][n+1-j]));
        }
    }
    cout << max(solve1(),solve2());
    return 0;
}