def get_resource_string(arn):
    """
    Given an ARN, return the string after the account ID, no matter the ARN format.

    :param arn: arn:partition:service:region:account-id:resourcetype/resource
    :return: resourcetype/resource
    """
    split_arn = arn.split(':')
    resource_string = ':'.join(split_arn[5:])
    return resource_string
