paragraph_text: From 1978 until 1988, an image of Newton designed by Harry Ecclestone appeared on Series D £1 banknotes issued by the Bank of England (the last £1 notes to be issued by the Bank of England). Newton was shown on the reverse of the notes holding a book and accompanied by a telescope, a prism and a map of the Solar System.

paragraph_text: Banknotes of the Pound Sterling Pound sterling banknotes The UK & crown dependencies (red) and overseas territories (blue) using the Pound or their local issue ISO 4217 Code GBP (Great Britain Pound) Denominations Currency symbol £Subunit Penny (1 / 100) Subunit symbol p Banknotes Freq. used £5, £10, £20, £50 Rarely used £1 (Not used by the Bank of England or in NI), £100 (Not used by the Bank of England) Higher valued Banknotes do exist, such as the £1,000,000 (Giant) and £100,000,000 (Titan), however, usage is restricted ``- such as through backing Scottish and Northern Ireland Currencies ''Demographics Users United Kingdom Jersey Guernsey Isle of Man South Georgia and the South Sandwich Islands St Helena, Ascension and Tristan da Cunha (Tristan da Cunha only) Gibraltar. Issuance Central Bank Bank of England Note - issuing banks England and Wales Bank of England Scotland Bank of Scotland Royal Bank of Scotland Clydesdale Bank Northern Ireland Northern Bank / Danske Bank First Trust Bank Ulster Bank Bank of Ireland Crown dependencies States of Guernsey States of Jersey Isle of Man Government Printer De La Rue

paragraph_text: The British Crown dependencies of Guernsey and Jersey produce their own local issues of sterling: the ``Guernsey pound ''and the`` Jersey pound''. The pound sterling is also used in the Isle of Man (alongside the Manx pound), Gibraltar (alongside the Gibraltar pound), the Falkland Islands (alongside the Falkland Islands pound), Saint Helena and Ascension Island in Saint Helena, Ascension and Tristan da Cunha (alongside the Saint Helena pound). The Bank of England is the central bank for the pound sterling, issuing its own coins and banknotes, and regulating issuance of banknotes by private banks in Scotland and Northern Ireland. Banknotes issued by other jurisdictions are not regulated by the Bank of England; local governments use Bank of England notes as backing for local issuance by allowing them to be exchanged 1: 1 at face value.

paragraph_text: The Federal Reserve System (also known as the Federal Reserve or simply the Fed) is the central banking system of the United States. It was created on December 23, 1913, with the enactment of the Federal Reserve Act, after a series of financial panics (particularly the panic of 1907) led to the desire for central control of the monetary system in order to alleviate financial crises. Over the years, events such as the Great Depression in the 1930s and the Great Recession during the 2000s have led to the expansion of the roles and responsibilities of the Federal Reserve System.

paragraph_text: The euro is managed and administered by the Frankfurt-based European Central Bank (ECB) and the Eurosystem (composed of the central banks of the eurozone countries). As an independent central bank, the ECB has sole authority to set monetary policy. The Eurosystem participates in the printing, minting and distribution of notes and coins in all member states, and the operation of the eurozone payment systems.

paragraph_text: Currently printed denominations are $1, $2, $5, $10, $20, $50, and $100. Notes above the $100 denomination stopped being printed in 1946 and were officially withdrawn from circulation in 1969. These notes were used primarily in inter-bank transactions or by organized crime; it was the latter usage that prompted President Richard Nixon to issue an executive order in 1969 halting their use. With the advent of electronic banking, they became less necessary. Notes in denominations of $500, $1,000, $5,000, $10,000 and $100,000 were all produced at one time; see large denomination bills in U.S. currency for details. These notes are now collectors' items and are worth more than their face value to collectors.

paragraph_text: The original, round £1 coin replaced the Bank of England £1 note, which ceased to be issued at the end of 1984 and was removed from circulation on 11 March 1988, though still redeemable at the Bank's offices, like all English banknotes. One - pound notes continue to be issued in Jersey, Guernsey and the Isle of Man, and by the Royal Bank of Scotland, but the pound coin is much more widely used. A new, dodecagonal (12 - sided) design of coin was introduced on 28 March 2017 and both new and old versions of the one pound coin circulated together until the older design was withdrawn from circulation on 15 October 2017. After that date, the older coin could only be redeemed at banks, although some retailers announced they would continue to accept it for a limited time. The original round pound remains legal tender on the Isle of Man.

paragraph_text: The Central Bank of Cuba (, BCC) is the central bank of Cuba. It was created in 1997 to take over many of the functions of the National Bank of Cuba (). From its creation until May 2009, the president was Francisco Soberón Valdés, and the current head is Irma Margarita Martínez Castrillón.

paragraph_text: The U.S. Constitution provides that Congress shall have the power to "borrow money on the credit of the United States". Congress has exercised that power by authorizing Federal Reserve Banks to issue Federal Reserve Notes. Those notes are "obligations of the United States" and "shall be redeemed in lawful money on demand at the Treasury Department of the United States, in the city of Washington, District of Columbia, or at any Federal Reserve bank". Federal Reserve Notes are designated by law as "legal tender" for the payment of debts. Congress has also authorized the issuance of more than 10 other types of banknotes, including the United States Note and the Federal Reserve Bank Note. The Federal Reserve Note is the only type that remains in circulation since the 1970s.

paragraph_text: The Federal Reserve Act (ch. 6, 38 Stat. 251, enacted December 23, 1913, 12 U.S.C. § § 221 to 522) is an Act of Congress that created and established the Federal Reserve System (the central banking system of the United States), and which created the authority to issue Federal Reserve Notes (commonly known as the US Dollar) as legal tender. The Act was signed into law by President Woodrow Wilson.

paragraph_text: Hafizullah Amin (Pashto/Dari: حفيظ الله امين‎; born 1 August 1929 – 27 December 1979) was an Afghan communist politician during the Cold War. Amin was born in Paghman and educated at Kabul University, after which he started his career as a teacher. After a few years in that occupation, he went to the United States to study. He would visit the United States a second time before moving permanently to Afghanistan, and starting his career in radical politics. He ran as a candidate in the 1965 parliamentary election but failed to secure a seat. Amin was the only Khalqist elected to parliament in the 1969 parliamentary election, thus increasing his standing within the party. He was one of the leading organizers of the Saur Revolution which overthrew the government of Mohammad Daoud Khan. In 1979 he named himself president, prime minister, and chairman of the Khalq wing. He has been described as "ruthless" and a "radical Marxist".Amin's short-lived presidency was marked by controversies from beginning to end. He came to power by disposing of his predecessor Nur Muhammad Taraki and later ordering his death. Amin made attempts to win support from those who revolted against the communist regime which had begun under Taraki, but his government was unable to solve this problem. Many Afghans held Amin responsible for the regime's harshest measures, such as ordering thousands of executions. Thousands of people disappeared without trace during his time in office. The Soviet Union, which was dissatisfied with Amin, intervened in Afghanistan while invoking the Twenty-Year Treaty of Friendship between Afghanistan and the Soviet Union. Amin was assassinated by the Soviets on December 27, 1979 as part of Operation Storm-333, having ruled for slightly longer than three months.

paragraph_text: Twenty pound notes were introduced by the Bank of England for the first time in 1725. The earliest notes were handwritten, and were issued to individuals as needed. These notes were written on one side only and bore the name of the payee, the date, and the signature of the issuing cashier. With the exception of the Restriction Period between 1797 and 1821 when the French Revolutionary Wars and the Napoleonic Wars caused a bullion shortage, these notes could be exchanged in full, or in part, for an equivalent amount of gold when presented at the bank. If redeemed in part, the banknote would be signed to indicate the amount that had been redeemed. From 1853 printed notes replaced handwritten notes, with the declaration ``I promise to pay the bearer on demand the sum of twenty pounds ''replacing the name of the payee. This declaration remains on Bank of England banknotes to this day. A printed signature of one of three cashiers appeared on the printed notes, though this was replaced by the signature of the Chief Cashier from 1870 onward.

paragraph_text: Regular government issues commenced in 1948 in denominations of 1, 5, 10 and 100 rupees. The government continued to issue 1 rupee notes until the 1980s but other note issuing was taken over by the State Bank of Pakistan in 1953, when 2, 5, 10 and 100 rupees notes were issued. Only a few 2 rupees notes were issued. 50 rupees notes were added in 1957, with 2 rupees notes reintroduced in 1985. In 1986, 500 rupees notes were introduced, followed by 1000 rupees the next year. 2 and 5 rupees notes were replaced by coins in 1998 and 2002. 20 rupee notes were added in 2005, followed by 5000 rupees in 2006. Until 1971, Pakistani banknotes were bilingual, featuring Bengali translation of the Urdu text (where the currency was called taka instead of rupee), since Bengali was the state language of East Pakistan (now Bangladesh).

paragraph_text: The Reserve Bank of Australia (RBA), on 14 January 1960, became the Australian central bank and banknote issuing authority, when the Reserve Bank Act 1959 (23 April 1959) removed the central banking functions from the Commonwealth Bank.

paragraph_text: The banks in effect borrow cash and must pay it back; the short durations allow interest rates to be adjusted continually. When the repo notes come due the participating banks bid again. An increase in the quantity of notes offered at auction allows an increase in liquidity in the economy. A decrease has the contrary effect. The contracts are carried on the asset side of the European Central Bank's balance sheet and the resulting deposits in member banks are carried as a liability. In layman terms, the liability of the central bank is money, and an increase in deposits in member banks, carried as a liability by the central bank, means that more money has been put into the economy.[a]

paragraph_text: The Bank of England £5 note, also known as a fiver, is a banknote of the pound sterling. It is the smallest denomination of banknote issued by the Bank of England. In September 2016, a new polymer note was introduced, featuring the image of Queen Elizabeth II on the obverse and a portrait of Winston Churchill on the reverse. The old paper note, first issued in 2002 and bearing the image of prison reformer Elizabeth Fry on the reverse, was phased out and ceased to be legal tender after 5 May 2017.

paragraph_text: The state Bank of Indiana was a government chartered banking institution established in 1833 in response to the state's shortage of capital caused by the closure of the Second Bank of the United States by the administration of President Andrew Jackson. The bank operated for twenty-six years and allowed the state to finance its internal improvements, stabilized the state's currency problems, and encouraged greater private economic growth. The bank closed in 1859. The profits were then split between the shareholders, allowing depositors to exchange their bank notes for federal notes, and the bank's buildings and infrastructure were sold and reincorporated as the privately owned Second Bank of Indiana.

paragraph_text: On January 1, 1973, the Central Bank of Nigeria introduced notes for 50 kobo, 1, 5, 10 and 20 naira. The 50 kobo notes were last issued in 1989. In 1991, 50 naira notes were issued, followed by 100 naira in 1999, 200 naira in 2000, 500 naira in 2001 and 1000 naira on October 12, 2005.

paragraph_text: Fifty pound notes were introduced by the Bank of England for the first time in 1725. The earliest notes were handwritten and were issued as needed to individuals. These notes were written on one side only and bore the name of the payee, the date, and the signature of the issuing cashier. With the exception of the Restriction Period between 1797 and 1821, when the French Revolutionary Wars and the Napoleonic Wars caused a bullion shortage, these notes could be exchanged in full, or in part, for an equivalent amount of gold when presented at the bank. If redeemed in part, the banknote would be signed to indicate the amount that had been redeemed. From 1853 printed notes replaced handwritten notes, with the declaration ``I promise to pay the bearer on demand the sum of fifty pounds ''replacing the name of the payee. This declaration remains on Bank of England banknotes to this day. A printed signature of one of three cashiers appeared on the printed notes, although this was replaced by the signature of the Chief Cashier from 1870 onward.

paragraph_text: The Bank of Sierra Leone is the central bank of Sierra Leone. It issues the country's currency, known as the Leone. The bank formulates and implements monetary policy, including foreign exchange.

Question: What are the notes issued by the current central bank of the country Amin visited twice?
Answer: obligations of the United States