import time


def get_running_time(time_start):
    """Returns the running time on format: <hours>h:<minutes>m:<seconds>s."""
    m, s = divmod(time.time() - time_start, 60)
    h, m = divmod(m, 60)
    return "{}h:{:02d}m:{:02d}s".format(int(h), int(m), int(s))