Question: What portion of the Nile runs from the country they migrate from to the country Al-Ubayyid is located?

full_context: Document 1: Sobat River: The Sobat River is a river of the Greater Upper Nile region in northeastern South Sudan, Africa. It is the most southerly of the great eastern tributaries of the White Nile, before the confluence with the Blue Nile.
Document 2: Jews: Between 1948 and 1958, the Jewish population rose from 800,000 to two million. Currently, Jews account for 75.4% of the Israeli population, or 6 million people. The early years of the State of Israel were marked by the mass immigration of Holocaust survivors in the aftermath of the Holocaust and Jews fleeing Arab lands. Israel also has a large population of Ethiopian Jews, many of whom were airlifted to Israel in the late 1980s and early 1990s. Between 1974 and 1979 nearly 227,258 immigrants arrived in Israel, about half being from the Soviet Union. This period also saw an increase in immigration to Israel from Western Europe, Latin America, and North America.
Document 3: Flooding of the Nile: The flooding of the Nile is the result of the yearly monsoon between May and August causing enormous precipitations on the Ethiopian Highlands whose summits reach heights of up to 4550 m (14,928 ft). Most of this rainwater is taken by the Blue Nile and by the Atbarah River into the Nile, a less important amount is flowing through the Sobat and the White Nile into the Nile. During this short period, those rivers contribute up to ninety percent of the water of the Nile and most of the sedimentation carried by it, but after the rainy season, dwindle to minor rivers.
Document 4: Umm Bel: Umm Bel is a town in North Kurdufan State in central Sudan, about 170 kilometres west of El Obeid, and north of En Nahud.
Document 5: Abyei District: Abyei District was a former district of Sudan, considered part of the state of West Kurdufan. Upon the dissolution of West Kurdufan in 2005, it was included in the state of South Kurdufan. Its administrative centre was the town of Abyei.
Document 6: University of Kordofan: The University of Kordofan (Arabic: جامعة كردفان ) (informally Kordofan University) is one of the largest universities in Sudan located in El-Obeid 560 km to the southwest of Khartoum. It was founded in 1990. University of Kordofan is recognized as one of the top universities in Sudan. It features several institutes, academic units and research centres including Institute of Gum Arabic Research and Desertification Studies, Centre for Intermediate Technology in Agriculture and Deanship for Scientific Research and Postgraduate Studies. It is a member of the Federation of the Universities of the Islamic World.
Document 7: Black people: About 150,000 East African and black people live in Israel, amounting to just over 2% of the nation's population. The vast majority of these, some 120,000, are Beta Israel, most of whom are recent immigrants who came during the 1980s and 1990s from Ethiopia. In addition, Israel is home to over 5,000 members of the African Hebrew Israelites of Jerusalem movement that are descendants of African Americans who emigrated to Israel in the 20th century, and who reside mainly in a distinct neighborhood in the Negev town of Dimona. Unknown numbers of black converts to Judaism reside in Israel, most of them converts from the United Kingdom, Canada, and the United States.
Document 8: Egypt: With over 90 million inhabitants, Egypt is the most populous country in North Africa and the Arab World, the third-most populous in Africa (after Nigeria and Ethiopia), and the fifteenth-most populous in the world. The great majority of its people live near the banks of the Nile River, an area of about 40,000 square kilometres (15,000 sq mi), where the only arable land is found. The large regions of the Sahara desert, which constitute most of Egypt's territory, are sparsely inhabited. About half of Egypt's residents live in urban areas, with most spread across the densely populated centres of greater Cairo, Alexandria and other major cities in the Nile Delta.
Document 9: Nile: The Nile (Arabic: النيل‎, written as al-Nīl; pronounced as an-Nīl) is a major north-flowing river in northeastern Africa, and is the longest river in Africa and the disputed longest river in the world (Brazilian government claims that the Amazon River is longer than the Nile). The Nile, which is about 6,650 km (4,130 mi) long, is an "international" river as its drainage basin covers eleven countries, namely, Tanzania, Uganda, Rwanda, Burundi, the Democratic Republic of the Congo, Kenya, Ethiopia, Eritrea, South Sudan, Republic of the Sudan and Egypt. In particular, the Nile is the primary water source of Egypt and Sudan.The river Nile has two major tributaries, the White Nile and Blue Nile. The White Nile is considered to be the headwaters and primary stream of the Nile itself. The Blue Nile, however, is the source of most of the water and silt. The White Nile is longer and rises in the Great Lakes region of central Africa, with the most distant source still undetermined but located in either Rwanda or Burundi. It flows north through Tanzania, Lake Victoria, Uganda and South Sudan.  The Blue Nile begins at Lake Tana in Ethiopia and flows into Sudan from the southeast. The two rivers meet just north of the Sudanese capital of Khartoum.The northern section of the river flows north almost entirely through the Sudanese desert to Egypt, then ends in a large delta and flows into the Mediterranean Sea. Egyptian civilization and Sudanese kingdoms have depended on the river since ancient times. Most of the population and cities of Egypt lie along those parts of the Nile valley north of Aswan, and nearly all the cultural and historical sites of Ancient Egypt are found along river banks.
Document 10: Atbarah River: The Atbarah River (; transliterated: Nahr 'Atbarah) in northeast Africa rises in northwest Ethiopia, approximately 50 km north of Lake Tana and 30 km west of Gondar. It flows about 805 km (500 mi) to the Nile in north-central Sudan, joining it at the city of Atbarah (). The river's tributary, the Tekezé (Setit) River, is perhaps the true upper course of the Atbarah, as the Tekezé follows the longer course prior to the confluence of the two rivers (at 14° 10' N, 36° E) in northeastern Sudan. The Atbarah is the last tributary of the Nile before it reaches the Mediterranean.
Document 11: Israel: In 2016, Israel's population was an estimated 8,476,600 million people, of whom 6,345,400 (74.9%) were recorded by the civil government as Jews. 1,760,400 Arabs comprised 20.7% of the population, while non-Arab Christians and people who have no religion listed in the civil registry made up 4.4%. Over the last decade, large numbers of migrant workers from Romania, Thailand, China, Africa, and South America have settled in Israel. Exact figures are unknown, as many of them are living in the country illegally, but estimates run in the region of 203,000. By June 2012, approximately 60,000 African migrants had entered Israel. About 92% of Israelis live in urban areas.
Document 12: Israel: Israel was established as a homeland for the Jewish people and is often referred to as a Jewish state. The country's Law of Return grants all Jews and those of Jewish ancestry the right to Israeli citizenship. Over three quarters, or 75.5%, of the population are Jews from a diversity of Jewish backgrounds. Around 4% of Israelis (300,000), ethnically defined as "others", are Russian descendants of Jewish origin or family who are not Jewish according to rabbinical law, but were eligible for Israeli citizenship under the Law of Return. Approximately 75% of Israeli Jews are born in Israel, 17% are immigrants from Europe and the Americas, and 8% are immigrants from Asia and Africa (including the Arab World). Jews from Europe and the former Soviet Union and their descendants born in Israel, including Ashkenazi Jews, constitute approximately 50% of Jewish Israelis. Jews who left or fled Arab and Muslim countries and their descendants, including both Mizrahi and Sephardi Jews, form most of the rest of the Jewish population. Jewish intermarriage rates run at over 35% and recent studies suggest that the percentage of Israelis descended from both Sephardi and Ashkenazi Jews increases by 0.5 percent every year, with over 25% of school children now originating from both communities.
Document 13: En Nahud: En Nahud is a town in the desert of central Sudan. Formerly located within the Sudanese political division of West Kurdufan, it is now part of the country's North Kurdufan state.
Document 14: Al-Fulah: Al-Fulah is a town in West Kordofan State in Sudan and is the capital of the state. The Chinese have shown an interest in developing a power station in Al-Fulah and building a pipeline. Conflict during the Second Sudanese Civil War resulted in many people being displaced. It is the home of the University of West Kordofan.
Document 15: Demographics of Israel: According to Israel's Central Bureau of Statistics, in 2008, of Israel's 7.3 million people, 75.6 percent were Jews of any background. Among them, 70.3 percent were Sabras (born in Israel), mostly second- or third-generation Israelis, and the rest are olim (Jewish immigrants to Israel)—20.5 percent from Europe and the Americas, and 9.2 percent from Asia and Africa, including the Arab countries.The paternal lineage of the Jewish population of Israel as of 2015 is as follows:
ground_truth: Blue Nile
sub_queries: Where did they migrate from? Answer: Ethiopia.
Al-Ubayyid >> country Answer: Sudan
Which portion of the Nile runs from Ethiopia. to #2 ? Answer: Blue Nile