#include <iostream>
#include <vector>
#include <string>
using namespace std;

int main(){
	int N; cin>>N;
	if (N==3){
		cout<<".#."<<endl;
		cout<<"###"<<endl;
		cout<<".#."<<endl;
	} else {
		string ret = "";
		for (int i=0; i<N; i++) ret += '.';
		ret[N-2] = '#';
		cout<<ret<<endl;
		ret[N-3] = '#';
		ret[N-1] = '#';
		for (int i=1; i<N-1; i++){
			cout<<ret<<endl;
			ret[N-i] = '.';
			if (N-i-3>=0) ret[N-i-3] = '#';
		}
		ret[0] = '.';
		ret[2] = '.';
		cout<<ret<<endl;
	}
}