from typing import List, Optional


class Cell:
    """Клетка лабиринта"""
    
    def __init__(self, x: int, y: int):
        self.x = x
        self.y = y
        self.is_wall = False
        self.is_start = False
        self.is_exit = False
    
    def is_passable(self) -> bool:
        """Проверяет, можно ли пройти через клетку"""
        return not self.is_wall
    
    def __eq__(self, other) -> bool:
        if not isinstance(other, Cell):
            return False
        return self.x == other.x and self.y == other.y
    
    def __hash__(self):
        return hash((self.x, self.y))
    
    def __repr__(self):
        return f"Cell({self.x}, {self.y})"


class Maze:
    """Лабиринт (сетка клеток)"""
    
    def __init__(self, width: int, height: int):
        self.width = width
        self.height = height
        self._cells: List[List[Optional[Cell]]] = [[None for _ in range(width)] for _ in range(height)]
        self.start: Optional[Cell] = None
        self.exit: Optional[Cell] = None
    
    def set_cell(self, x: int, y: int, cell: Cell) -> None:
        """Устанавливает клетку в указанные координаты"""
        if 0 <= x < self.width and 0 <= y < self.height:
            self._cells[y][x] = cell
            if cell.is_start:
                self.start = cell
            if cell.is_exit:
                self.exit = cell
    
    def get_cell(self, x: int, y: int) -> Optional[Cell]:
        """Возвращает клетку по координатам"""
        if 0 <= x < self.width and 0 <= y < self.height:
            return self._cells[y][x]
        return None
    
    def get_neighbors(self, cell: Cell) -> List[Cell]:
        """Возвращает список соседних проходимых клеток"""
        neighbors = []
        directions = [(0, -1), (0, 1), (-1, 0), (1, 0)]  # вверх, вниз, влево, вправо
        
        for dx, dy in directions:
            nx, ny = cell.x + dx, cell.y + dy
            neighbor = self.get_cell(nx, ny)
            if neighbor and neighbor.is_passable():
                neighbors.append(neighbor)
        
        return neighbors
    
    def __str__(self) -> str:
        """Строковое представление лабиринта"""
        result = []
        for y in range(self.height):
            row = []
            for x in range(self.width):
                cell = self.get_cell(x, y)
                if cell is None:
                    row.append('?')
                elif cell.is_start:
                    row.append('S')
                elif cell.is_exit:
                    row.append('E')
                elif cell.is_wall:
                    row.append('#')
                else:
                    row.append(' ')
            result.append(''.join(row))
        return '\n'.join(result)