#include <bits/stdc++.h>
using namespace std;
#define int long long

#define REP(i,n) for(int i = 0; i < n; i++)
#define REPP(i, a, n) for(int i = a; i < n; i++)
#define RI(n) for(int i = 0; i < n; i++)
#define IN(n) int n; cin>>n;
#define OUT(x) cout<<x<<'\n';
#define DBG(x) cout<<#x<<" = "<<x<<'\n';
#define VI vector<int>
#define ENDL cout<<'\n';
#define STOP system("pause");
#define pb push_back
#define mp make_pair
int inf = 1e18 * 2;

main(){
    //ios_base::sync_with_stdio(false);
    //cin.tie(0);
    //cout.tie(0);

    IN(n)
    IN(m)
    n+=2;
    m+=2;
    vector<vector<bool>>home(n, vector<bool>(m, false));
    vector<vector<bool>>water(n, vector<bool>(m, false));
    REP(i, n - 2)
    REP(j, m - 2){
        char c;
        cin>>c;
        if(c!='.')home[i + 1][j + 1] = true;
    }
    REP(i, n - 2)
    REP(j, m - 2){
        char c;
        cin>>c;
        if(c!='.')water[i + 1][j + 1] = true;
    }
    //DBG("11")
    int ans = 0;
    for(int i = -n; i <= n; i++){
        //DBG(i)
        for(int j = -m; j <= m; j++){

            bool b = false;
            int curr = 0;
            REP(x, n){
                //DBG(x)
                REP(y, m){
                    int x1 = x + i;
                    int y1 = y + j;
                    if(x1 < 0 || y1 < 0)continue;
                    if(x1 >= n || y1 >= m)continue;
                    if(water[x][y] && home[x1][y1]){
                        b = true;
                        break;
                    }
                    if(home[x1][y1]){
                        for(int x_ = max((int)0, x - 1); x_ <= min(x + 1, n - 1); x_++){
                            for(int y_ = max((int)0, y - 1); y_ <= min(y + 1, m - 1); y_++){
                                //DBG(x_)
                                //DBG(y_)
                                if(water[x_][y_] && (x_ - x == 0 || y_ - y == 0)){
                                    //DBG("124")
                                    curr++;
                                }
                                //DBG("11111")
                            }
                        }
                    }
                    //DBG("!!!!")
                }
                //  DBG("abcdt")
                //DBG(b)
                if(b)break;
            }
            if(!b){
                ans = max(ans, curr);
            }
        }
    }
    OUT(ans)


    return 0;
}