Расстановка N ферзей на шахматной доске N×N

n = int(input())
remainder = n % 6
#If the remainder is 2, swap 1 and 3
#in odd list and move 5 to the end.
if remainder == 2:
    even = list(range(1, n, 2))
    odd = list(range(2, n, 2))
    odd[1] = 0
    odd.append(4)
#If the remainder is 3, move 2
#to the end of even list and 1, 3
#to the end of odd list.
elif remainder == 3:
    even = list(range(3, n, 2))
    even.append(1)
    odd = list(range(4, n, 2))
    odd.append(0)
    odd.append(2)
#If the remainder from dividing n by 6
#is not 2 or 3 then the list is simply
#all even numbers followed by all
#odd numbers not greater than n.
else:
    even = list(range(1, n, 2))
    odd = list(range(0, n, 2))
#Append odd list to the even list
#and place queens in the rows
#given by these numbers.
result = even + odd
row = ['.'] * n
for i in range(n):
    j = result[i]
    row[j] = 'Ф'
    print(*row)
    row[j] = '.'

n = 7
 
field = [['.'] * n for _ in range(n)]
j = 0 if n % 2 else 1
 
for i in range(n):
    field[i][j] = 'Ф'
    j = (j + 2) % n
    if n % 2 == 0 and i == (n // 2) - 1:
        j -= 1
 
for row in field:
    print(''.join(row))

global n,fld
n=int(input("n="))
fld=[[0 for _ in range(n)] for _ in range(n)]
 
def mark_fld(r,c,z):
    global n,fld
    i=c+1
    while(i<n):
        fld[r][i]+=z
        i+=1
    i=c-1
    while(i>=0):
        fld[r][i]+=z
        i-=1
    j=r+1
    while(j<n):
        fld[j][c]+=z
        j+=1
    j=r-1
    while(j>=0):
        fld[j][c]+=z
        j-=1;
    i,j=r-1,c+1
    while(i>=0 and j<n):
        fld[i][j]+=z
        i-=1
        j+=1
    i,j=r-1,c-1
    while(i>=0 and j>=0):
        fld[i][j]+=z
        i-=1
        j-=1  
    i,j=r+1,c+1
    while(i<n and j<n):
        fld[i][j]+=z
        i+=1
        j+=1
    i,j=r+1,c-1
    while(i<n and j>=0):
        fld[i][j]+=z
        i+=1
        j-=1   
    fld[r][c]+=z    
 
def queen(c,q=[]):
    global n,fld
    if c==n:
        return
    k=0 
    while(k<n):
        if fld[k][c]==0:
            mark_fld(k,c,1)
            u=q+[(k,c)]
            if len(u)==n:
                print("!!!",u)
            queen(c+1,u)
            mark_fld(k,c,-1)
        k+=1
 
queen(0)