def getch():
    fd = sys.stdin.fileno()
    old_settings = termios.tcgetattr(fd)
    try:
        tty.setraw(fd)
        ch = sys.stdin.read(1)
    except KeyboardInterrupt:
        raise
    finally:
        termios.tcsetattr(fd, termios.TCSADRAIN, old_settings)
    return ch