#include<bits/stdc++.h>
#define ll long long
#pragma GCC optimize(2)
#define un unsigned
#define db double
#define st string
#define ct const
#define xh(a,b,c) for(int a=b;a<=c;a++)
#define wx while(1)
#define dn(a,b,c) for(int a=b;a>=c;a--)
using namespace std;
int n,maxn;
char a[30][30];
int f[30][30];
int tj(){
	int ans=0;
	xh(i,1,20)xh(j,1,20)ans+=(f[i][j]==2&&a[i][j]=='#');
	return ans;
}
void dfs(int k,int start,int ans,bool flag){
	if(k==n+1){
		maxn=max(maxn,tj());
		return ;
	}
	if(!flag){
		xh(i,start,20){
			xh(j,1,20)f[i][j]++;
			dfs(k+1,i+1,ans,flag);
			dfs(k+1,1,ans,1);
			xh(j,1,20)f[i][j]--;
		}
	}
	else{
		xh(i,start,20){
			xh(j,1,20)f[j][i]++;
			dfs(k+1,i+1,ans,flag);
			xh(j,1,20)f[j][i]--;
		}
	}
}
signed main(){
	cin>>n;
	xh(i,1,20)xh(j,1,20)cin>>a[i][j];
	dfs(1,1,0,0);
	cout<<maxn;
	return 0;
}