question: Who is Olga Constantinovna Of Russia's maternal grandfather?
context: [["Princess Vera Constantinovna of Russia", ["Princess Vera Constantinovna of Russia, also Vera Konstantinovna( 24 April 1906 \u2013 11 January 2001), was the youngest child of Grand Duke Konstantine Konstantinovich of Russia and his wife, Grand Duchess Elizabeth Mavrikievna.", "A great- granddaughter of Tsar Nicholas", "I of Russia, she was born in the Russian Empire and was a childhood playmate of the younger children of Emperor Nicholas II of Russia.", "She lost much of her family during World War I and the Russian Revolution.", "At age twelve, she escaped revolutionary Russia, fleeing with her mother and brother George to Sweden.", "She spent the rest of her long life in exile, first in Western Europe and from the 1950s in the United States."]], ["Abdul-Vahed Niyazov", ["' of Russia."]], ["Henry Krause", ["Henry J.\" Red\" Krause, Jr.( August 28, 1913 \u2013 February 20, 1987) was an American football offensive lineman in the National Football League for the Brooklyn Dodgers and the Washington Redskins.", "He played college football at St. Louis University.", "He is the grandfather of Jennifer Krause", "He is the great grandfather of Payton Hoeing"]], ["Princess Anastasia of Greece and Denmark", ["Princess Anastasia of Greece and Denmark (\"n\u00e9e\" Nonie May Stewart; 20 January 1878 \u2013 29 August 1923) was an American-born heiress and member of the Greek Royal Family.", "She was married to Prince Christopher of Greece and Denmark, the youngest child of King George I of Greece and his consort, Grand Duchess Olga Constantinovna of Russia, but was created a princess \"suo jure\"."]], ["Abd al-Muttalib", ["Abd al- Muttalib Shaybah ibn Hashim( c. 497 \u2013 578) was the grandfather of Islamic prophet Muhammad."]], ["Princess Eug\u00e9nie of Greece and Denmark", ["Princess Eug\u00e9nie of Greece and Denmark( 10 February 1910 \u2013 13 February 1989) was the youngest child and only daughter of Prince George of Greece and Denmark and his wife, Princess Marie Bonaparte, daughter of Marie- F\u00e9lix Blanc and Prince Roland Bonaparte, a great- nephew of Napoleon I.", "Her father was the second son of George I of Greece and Olga Constantinovna of Russia.", "As a cousin of the bridegroom, she was a leading guest at the 1947 wedding of Princess Elizabeth and Philip, Duke of Edinburgh.", "She authored\" Le Tsarevitch, Enfant Martyr\", a biography of Aleksey Nikolaevich, Tsarevich of Russia, written in French, which was published in 1990."]], ["Olga Constantinovna of Russia", ["Olga Constantinovna of Russia (18 June 1926) was Queen consort of the Hellenes as the wife of King George I.", "She was briefly the regent of Greece in 1920.", "A member of the Romanov dynasty", ", she was the daughter of Grand Duke Constantine Nikolaievich and his wife, Princess Alexandra of Saxe-Altenburg.", "She spent her childhood in Saint Petersburg, Poland and the Crimea, and married King George I of Greece in 1867 at the age of sixteen.", "At first, she felt ill at ease in the Kingdom of Greece, but she quickly became involved in social and charitable work.", "She founded hospitals and schools, but her attempt to promote a new, more accessible, Greek translation of the Gospels sparked riots by religious conservatives.", "On the assassination of her husband in 1913, Olga returned to Russia.", "When the First World War broke out, she set up a military hospital in Pavlovsk Palace, which belonged to her brother.", "She was trapped in the palace after the Russian Revolution of 1917, until the Danish embassy intervened, allowing her to escape to Switzerland.", "Olga could not return to Greece as her son, King Constantine I, had been deposed.", "In October 1920, she returned to Athens on the fatal illness of her grandson, King Alexander.", "After his death, she was appointed regent until the restoration of Constantine I the following month.", "After the defeat of the Greeks in the Greco-Turkish War of 1919\u201322", "the Greek royal family were again exiled and Olga spent the last years of her life in the United Kingdom, France and Italy."]], ["Princess Alexandra of Saxe-Altenburg", ["Grand Duchess Alexandra Iosifovna of Russia (8 July 1830 \u2013 6 July 1911), born Princess Alexandra Friederike Henriette of Saxe-Altenburg, was the fifth daughter of Joseph, Duke of Saxe-Altenburg and Amelie Theresa Luise, Duchess of W\u00fcrttemberg.", "She is an ancestor of the British, Greek, Romanian, Yugoslavian and Spanish Royal Families through her elder daughter Olga."]], ["Fred Le Deux", ["Frederick\" Fred\" Le Deux( born 4 December 1934) was an Australian rules footballer who played with Geelong in the Victorian Football League( VFL).", "He is the grandfather of Tom Hawkins."]], ["Kaya Alp", ["Kaya Alp was, according to Ottoman tradition, the son of K\u0131z\u0131l Bu\u011fa and the father of Suleyman Shah, who was, in turn, the grandfather of Ertu\u011frul, and the great grandfather of the Ottoman Empire founder, Osman I."]]]
supporting_facts: [["Olga Constantinovna of Russia", 3], ["Princess Alexandra of Saxe-Altenburg", 0]]
evidences: [["Olga Constantinovna of Russia", "mother", "Princess Alexandra of Saxe-Altenburg"], ["Princess Alexandra of Saxe-Altenburg", "father", "Joseph, Duke of Saxe-Altenburg"]]
answer: Joseph, Duke of Saxe-Altenburg