import re
text = "I studied in King Saud University, which is in Riyadh, the capital of Saudi Arabia"
result = re.sub(r"\b[A-Z]\w*(?:\s+[A-Z]\w*)+", lambda x: "".join(c[0] for c in x.group().split()), text)
print(result)
aW1wb3J0IHJlCnRleHQgPSAiSSBzdHVkaWVkIGluIEtpbmcgU2F1ZCBVbml2ZXJzaXR5LCB3aGljaCBpcyBpbiBSaXlhZGgsIHRoZSBjYXBpdGFsIG9mIFNhdWRpIEFyYWJpYSIKcmVzdWx0ID0gcmUuc3ViKHIiXGJbQS1aXVx3Kig/OlxzK1tBLVpdXHcqKSsiLCBsYW1iZGEgeDogIiIuam9pbihjWzBdIGZvciBjIGluIHguZ3JvdXAoKS5zcGxpdCgpKSwgdGV4dCkKcHJpbnQocmVzdWx0KQ==