question: Who is the maternal grandfather of Princess Charlotte Sophie Of Saxe-Coburg-Saalfeld?
context: [["Princess Sophie of Saxe-Hildburghausen", ["Princess Sophie of Saxe- Hildburghausen( Ernestine Friederike Sophie; 22 February 1760, Hildburghausen \u2013 28 October 1776, Coburg), was a Princess of Saxe- Hildburghausen by birth, and by marriage she became the Hereditary Princess of Saxe- Coburg- Saalfeld."]], ["John Ernest IV, Duke of Saxe-Coburg-Saalfeld", ["Johann Ernest IV, Duke of Saxe- Coburg- Saalfeld( 22 August 1658 in Gotha \u2013 17 February 1729 in Saalfeld) was a reigning duke of Saxe- Coburg- Saalfeld."]], ["Francis Josias, Duke of Saxe-Coburg-Saalfeld", ["Francis Josias, Duke of Saxe- Coburg- Saalfeld( 25 September 1697, in Saalfeld \u2013 16 September 1764, in Rodach) was a duke of Saxe- Coburg- Saalfeld."]], ["Princess Sophia Wilhelmina of Saxe-Coburg-Saalfeld", ["Princess Sophia Wilhelmina of Saxe- Coburg- Saalfeld( 9 August 1693, in Saalfeld \u2013 4 December 1727, in Rudolstadt) was a Princess of Saxe- Coburg- Saalfeld by birth, and Princess of Schwarzburg- Rudolstadt by marriage."]], ["Princess Charlotte Sophie of Saxe-Coburg-Saalfeld", ["Princess Charlotte Sophie of Saxe-Coburg-Saalfeld, Duchess in Saxony (24 September 1731 \u2013 2 August 1810) was a German duchess.", "She was the daughter of Franz Josias, Duke of Saxe-Coburg-Saalfeld and Princess Anna Sophie of Schwarzburg-Rudolstadt.", "Through his brother Ernest Frederick, Duke of Saxe-Coburg-Saalfeld, she was grandaunt of King Leopold I of Belgium and great-grandaunt of King Leopold II of Belgium, Empress Carlota of Mexico, Queen Victoria of the United Kingdom and her consort Prince Albert."]], ["Princess Sophie of Saxe-Coburg-Saalfeld", ["Princess Sophie Friederike Karoline Luise of Saxe- Coburg- Saalfeld( 19 August 1778 \u2013 9 July 1835) was a princess of Saxe- Coburg- Saalfeld, and the sister of Princess Victoria of Saxe- Coburg- Saalfeld and King Leopold I of Belgium, and aunt of Queen Victoria.", "By marriage, she was a Countess of Mensdorff- Pouilly.", "She was born in Coburg, the eldest child of Francis, Duke of Saxe- Coburg- Saalfeld and Countess Augusta Reuss of Ebersdorf."]], ["Ernest Frederick, Duke of Saxe-Coburg-Saalfeld", ["Ernest Frederick, Duke of Saxe- Coburg- Saalfeld( 8 March 1724 in Saalfeld \u2013 8 September 1800 in Coburg), was a Duke of Saxe- Coburg- Saalfeld."]], ["Princess Juliane of Saxe-Coburg-Saalfeld", ["Princess Juliane Henriette Ulrike of Saxe-Coburg-Saalfeld (Coburg, 23 September 1781 \u2013 Elfenau, near Bern, Switzerland, 15 August 1860), also known as Grand Duchess Anna Feodorovna of Russia , was a German princess of the ducal house of Saxe-Coburg-Saalfeld (after 1826, the house of Saxe-Coburg-Gotha) who became the wife of Grand Duke Konstantin Pavlovich of Russia."]], ["Christian Ernest II, Duke of Saxe-Coburg-Saalfeld", ["Christian Ernst II, Duke of Saxe-Coburg-Saalfeld (Saalfeld, 18 August 1683 \u2013 Saalfeld, 4 September 1745), was a duke of Saxe-Coburg-Saalfeld."]], ["Princess Anna Sophie of Schwarzburg-Rudolstadt", ["Princess Anna Sophie of Schwarzburg-Rudolstadt (9 September 1700 \u2013 11 December 1780) was a Princess of Schwarzburg-Rudolstadt.", "She was the daughter of", "Louis Frederick I, Prince of Schwarzburg-Rudolstadt (15 October 1667 \u2013 24 June 1718) and Anna Sophie of Saxe-Gotha-Altenburg (1670\u20131728)."]]]
supporting_facts: [["Princess Charlotte Sophie of Saxe-Coburg-Saalfeld", 1], ["Princess Anna Sophie of Schwarzburg-Rudolstadt", 2]]
evidences: [["Princess Charlotte Sophie of Saxe-Coburg-Saalfeld", "mother", "Princess Anna Sophie of Schwarzburg-Rudolstadt"], ["Princess Anna Sophie of Schwarzburg-Rudolstadt", "father", "Louis Frederick I, Prince of Schwarzburg-Rudolstadt"]]
answer: Louis Frederick I, Prince of Schwarzburg-Rudolstadt