def weight(s, e, speed):
    """
    Returns the weight to be assigned to the edges of the graph.

    Parameters: (s, e, d)
        s - (lat, lon)
        e - (lat, lon)
        speed - int
    """
    return ((s[0] - e[0]) ** 2 + (s[1] - e[1]) ** 2) ** 0.5 / speed