import sys
from collections import deque
import heapq
import time
import os

class Cell:
    """клетка лабиринта"""
    def __init__(self, x, y, is_wall=False, is_start=False, is_exit=False):
        self.x = x
        self.y = y
        self.is_wall = is_wall
        self.is_start = is_start
        self.is_exit = is_exit
    
    def is_passable(self):
        return not self.is_wall
    
    def __repr__(self):
        return f"Cell({self.x}, {self.y})"


class Maze:
    """лабиринт"""
    def __init__(self, width, height):
        self.width = width
        self.height = height
        self.cells = [[Cell(x, y) for x in range(width)] for y in range(height)]
        self.start = None
        self.exit = None
    
    def get_cell(self, x, y):
        if 0 <= x < self.width and 0 <= y < self.height:
            return self.cells[y][x]
        return None
    
    def get_neighbors(self, cell):
        neighbors = []
        directions = [(-1, 0), (1, 0), (0, -1), (0, 1)]
        for dx, dy in directions:
            neighbor = self.get_cell(cell.x + dx, cell.y + dy)
            if neighbor and neighbor.is_passable():
                neighbors.append(neighbor)
        return neighbors
    
    def set_start(self, x, y):
        cell = self.get_cell(x, y)
        if cell:
            cell.is_start = True
            self.start = cell
    
    def set_exit(self, x, y):
        cell = self.get_cell(x, y)
        if cell:
            cell.is_exit = True
            self.exit = cell



class MazeBuilder:
    """интерфейс строителя лабиринта"""
    
    def buildFromFile(self, filename):
        raise NotImplementedError


class TextFileMazeBuilder(MazeBuilder):
    """загрузка лабиринта из текстового файла"""
    
    def buildFromFile(self, filename):
        with open(filename, 'r', encoding='utf-8') as f:
            lines = [line.rstrip('\n') for line in f.readlines()]
        
        height = len(lines)
        width = max(len(line) for line in lines) if height > 0 else 0
        
        for i in range(height):
            if len(lines[i]) < width:
                lines[i] = lines[i] + ' ' * (width - len(lines[i]))
        
        maze = Maze(width, height)
        start_count = 0
        exit_count = 0
        
        for y, line in enumerate(lines):
            for x, ch in enumerate(line):
                if ch == '#':
                    maze.get_cell(x, y).is_wall = True
                elif ch == 'S':
                    maze.set_start(x, y)
                    start_count += 1
                elif ch == 'E':
                    maze.set_exit(x, y)
                    exit_count += 1
                else:
                    maze.get_cell(x, y).is_wall = False
        
        if start_count != 1 or exit_count != 1:
            raise ValueError(f"Ошибка: S={start_count}, E={exit_count} (нужно по одному)")
        
        return maze