from typing import List, Optional


class Cell:
    """Клетка лабиринта."""
    
    def __init__(self, x: int, y: int, is_wall: bool = False,
                 is_start: bool = False, is_exit: bool = False, weight: int = 1):
        self.x = x
        self.y = y
        self.is_wall = is_wall
        self.is_start = is_start
        self.is_exit = is_exit
        self.weight = weight  # для взвешенных лабиринтов
    
    def is_passable(self) -> bool:
        return not self.is_wall
    
    def __repr__(self):
        if self.is_start:
            return 'S'
        elif self.is_exit:
            return 'E'
        elif self.is_wall:
            return '#'
        else:
            return ' '
    
    def __eq__(self, other):
        if isinstance(other, Cell):
            return self.x == other.x and self.y == other.y
        return False
    
    def __hash__(self):
        return hash((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[Cell]] = []
        self.start: Optional[Cell] = None
        self.exit: Optional[Cell] = None
        
        for y in range(height):
            row = []
            for x in range(width):
                row.append(Cell(x, y))
            self.cells.append(row)
    
    def get_cell(self, x: int, y: int) -> Optional[Cell]:
        if 0 <= x < self.width and 0 <= y < self.height:
            return self.cells[y][x]
        return None
    
    def set_cell(self, x: int, y: int, cell: Cell):
        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_neighbors(self, cell: Cell) -> List[Cell]:
        """Соседи сверху/снизу/слева/справа, если проходимы."""
        neighbors = []
        directions = [(0, -1), (0, 1), (-1, 0), (1, 0)]
        
        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 __repr__(self):
        lines = []
        for row in self.cells:
            lines.append(''.join(str(cell) for cell in row))
        return '\n'.join(lines)