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

int main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);

    int n;
    cin >> n;

    for (int row = 0; row < n; row++) {
        for (int col = 0; col < n; col++) {
            bool white = (row + col <= n - 3) || (row + col >= n + 1);
            cout << (white ? '.' : '#');
        }
        cout << '\n';
    }

    return 0;
}