import sys

class Cell:
    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


class Maze:
    def __init__(self, width, height, cells, start=None, exit=None):
        self.width = width
        self.height = height
        self.cells = cells
        self.start = start
        self.exit = exit

    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 = []
        for dx, dy in ((0, -1), (0, 1), (-1, 0), (1, 0)):
            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


class MazeBuilder:
    @staticmethod
    def build_from_file(filename):
        with open(filename, 'r') as f:
            lines = [line.rstrip('\n') for line in f]
        if not lines:
            raise ValueError("Empty file")
        height = len(lines)
        width = max(len(line) for line in lines)
        cells = []
        start = None
        exit_cell = None
        for y, line in enumerate(lines):
            row = []
            for x in range(width):
                ch = line[x] if x < len(line) else ' '
                is_wall = (ch == '#')
                is_start = (ch == 'S')
                is_exit = (ch == 'E')
                if is_start:
                    start = Cell(x, y, False, True, False)
                    row.append(start)
                elif is_exit:
                    exit_cell = Cell(x, y, False, False, True)
                    row.append(exit_cell)
                else:
                    row.append(Cell(x, y, is_wall, False, False))
            cells.append(row)
        if start is None:
            raise ValueError("No start cell (S) found")
        if exit_cell is None:
            raise ValueError("No exit cell (E) found")
        return Maze(width, height, cells, start, exit_cell)


def print_maze(maze):
    for y in range(maze.height):
        row = []
        for x in range(maze.width):
            cell = maze.get_cell(x, y)
            if cell.is_start:
                row.append('S')
            elif cell.is_exit:
                row.append('E')
            elif cell.is_wall:
                row.append('#')
            else:
                row.append(' ')
        print(''.join(row))


def main():
    if len(sys.argv) > 1:
        filename = sys.argv[1]
    else:
        filename = 'maze1.txt'
    try:
        maze = MazeBuilder.build_from_file(filename)
        print(f"Maze loaded ({maze.width}x{maze.height})")
        print_maze(maze)
    except Exception as e:
        print(f"Error: {e}")

if __name__ == '__main__':
    main()