8queen

def solve(board, col):
    if col == 8:
        return True

    for row in range(8):
        if all(board[row][i] == 0 for i in range(col)) and \
           all(board[row-i][col-i] == 0 for i in range(min(row, col) + 1)) and \
           all(board[row+i][col-i] == 0 for i in range(min(8-row, col + 1))):
            
            board[row][col] = 1
            
            if solve(board, col + 1):
                return True
                
            board[row][col] = 0

    return False

board = [[0] * 8 for _ in range(8)]

if solve(board, 0):
    for r in board:
        print(" ".join("Q" if x else "." for x in r))
else:
    print("No solution")