def compute_in_degrees(digraph):
    """
    Compute the in degrees of a diagraph
    :param digraph: a dictionary representing directed graph
    :return: a dictionary which is the in degrees
    """
    # Initialize as in-degrees of 0 for all nodes
    in_degrees = {i: 0 for i in digraph.keys()}

    for edge_lists in digraph.values():
        for vert in edge_lists:
            in_degrees[vert] += 1

    return in_degrees