from __future__ import annotations
import sys
sys.setrecursionlimit(2*10**7)
#↓codon===============================
import string
Alp_low=list(string.ascii_lowercase)
Alp_up=list(string.ascii_uppercase)
Digit="0123456789"
dij=[[0,1],[1,0],[0,-1],[-1,0]]
def nin():
    return list(map(int,input().split()))
def deq(x):
    return [i-1 for i in x]
mod=998244353
_factorial=[1]
def factorial(n):
    while len(_factorial)<=n:
        _factorial.append((_factorial[-1]*len(_factorial))%mod)
    return _factorial[n]

_inv_factorial=[1]
def inv_factorial(n):
    while len(_inv_factorial)<=n:
        _inv_factorial.append((_inv_factorial[-1]*pow(len(_inv_factorial),mod-2,mod))%mod)
    return _inv_factorial[n]

def binom(n,r):
    if r>=mod:
        raise ValueError("r is too big")
    if n<0:
        return 0
    if r>n:
        return 0
    if r<0:
        return 0
    ans=((factorial(n)*inv_factorial(r))%mod*inv_factorial(n-r))%mod
    return ans

def main():
    n,=nin()
    if n==3:
        print(".#.")
        print("###")
        print(".#.")
        return

    k=(-n+2)%4

    ans=[["."]*n for _ in range(n)]
    for i in range(n):
        for j in range(n):
            if (i,j) in [(0,n-1),(n-1,0),(0,n-2),(n-2,0)]:
                ans[i][j]="#"
                continue
            if i==n-1 or j==n-1 or i==0 or j==0:
                ans[i][j]="."
                continue
            if (i+j+k)%4 in [0,1]:
                ans[i][j]="#"
                continue
            continue
            if i==n-1 and j==0:
                ans[i][j]="#"
                continue
            if i in [0,n-1] or j in [0,n-1]:
                continue
    for i in ans:
        print("".join(i))
    


if __name__=="__main__":
    main()