#include<bits/stdc++.h>
using namespace std;
typedef long long int ll;
typedef long double ld;
typedef vector<int> vi;
typedef vector<ll> vl;
typedef vector<vl> vvl;
typedef vector<vvl> vvvl;
typedef vector<vvvl> vvvvl;
typedef vector<bool> vb;
typedef vector<vb> vvb;
typedef vector<vvb> vvvb;
typedef vector<vvvb> vvvvb;
typedef pair<ll,ll> pl;
typedef pair<ll,pl> ppl;
typedef pair<ll,ppl> pppl;
typedef pair<ll,pppl> pppppl;
#define rep(i,a,b) for(int i=(a);i<(b);i++)
#define rrep(i,a,b) for(int i=(b)-1;i>=(a);i--)
#define all(a) begin(a),end(a)
#define F first
#define S second
const ll mod=998244353;
const string als="abcdefghijklmnopqrstuvwxyz";
const string ALS="ABCDEFGHIJKLMNOPQRSTUVWXYZ";

int main(){
	int n;
	cin>>n;
	ll an=0;
	vector<vector<int>> v(n,vector<int>(2*n,0));
	vector<int> a(n,-n);
	rep(i,0,n){
		rep(j,0,2*n){
			char c;
			cin>>c;
			if(c=='#'){
				a[i]++;
				v[i][j]=1;
			}
		}
	}
	rep(i,0,n-1){
		int j=0;
		while(a[i]>0){
			if(v[i][j]>0){
				an++;
				v[i][j]=v[i][j]-1;
				v[i+1][j]++;
				a[i]=a[i]-1;
				a[i+1]++;
			}
			else{
				j++;
			}
		}
		while(a[i]<0){
			if(v[i+1][j]>0){
				an++;
				v[i+1][j]=v[i+1][j]-1;
				v[i][j]++;
				a[i]++;
				a[i+1]=a[i+1]-1;
			}
			else{
				j++;
			}
		}
	}
	
	rep(i,0,n){
		rep(j,0,2*n-1){
			if(v[i][j]>0 && j<n){
				an=an+v[i][j];
				v[i][j+1]=v[i][j]+v[i][j+1];
			}
			if(v[i][j]>1 && j>=n){
				an=an+v[i][j]-1;
				v[i][j+1]=v[i][j]+v[i][j+1]-1;
			}
		}
	}
	cout<<an<<endl;
}