def split_subdomains(host):
    parts = host.split('.')
    major = [parts.pop()]
    while (len(parts) > 0):
        part = parts.pop()
        major.insert(0, part)
        if (len(part) > 3):
            break
    return (('.'.join(major) + ':') + '.'.join(parts))
def split_subdomains(host):
    parts = host.split('.')
    major = [parts.pop()]
    while (len(parts) > 0):
        part = parts.pop()
        major.insert(0, part)
        if (len(part) > 3):
            break
    return (('.'.join(major) + ':') + '.'.join(parts))